Most orders in Legions of Lore don't happen until rollover. Up until the end of the turn, these orders can be cancelled or changed. However there are also some orders that take effect immediately. Once instant orders are given, they can't be undone, so don't screw them up. Plan carefully before you commit yourself. Instant actions include: all forms of scouting, researching tech, finding artifacts with an operative (but not equipping them), shifting SciFi units, and a number of spells and operative special abilities. Instant spells and operative specials will say so explicitly in their tooltip description.
Researching new tech can offer a variety of bonuses, such as allowing the creation of new types of units or buildings, allowing new spells, or increasing the effectiveness of existing units or spells. The types of techs available as well as what resources techs cost vary by genre. (Note that adventure has no tech at all, instead unlocking new units and abilities by upgrading adventurers.) The cost of a tech is listed in its tooltip along with whatever other prerequisites there might be. Researching tech is instant and so it can't be undone once the order is given. For more information about what techs each genre has check the genre pages.
Each turn you can recruit new units in any of the provinces you control. What types of units you can recruit in a given province depends on the specific unit requirements, although most genres have at least one type of unit that can be recruited in any province (except adventure which can only recruit units at an adventurer). Units cost resources to recruit, however in most cases recruit orders don't execute until rollover, so orders can be canceled anytime before the turn ends for a full refund. Units appear in the province where they were recruited at the beginning of next turn. They won't fight during the rollover when they are recruited. If the province where they're being recruited gets captured during rollover, they'll retreat to your neighboring territories (or die if there are none to retreat to). The main exception is during the first turn, when all recruit and build orders are instant. This allows you to build an army and attack with it on the first turn in order to move the game a bit faster at the beginning. For information on unit orders check the unit actions section in the mechanics page. For unit stats check the genre pages.
SciFi and Fantasy are the only genres with buildings. For the most part building buildings is similar to recruiting units, but buildings differ from units in that they're stationary, and their main purpose is to provide some benefit to the territory where they're built such as allowing the recruitment of new unit types. If a province with existing buildings or with buildings being built is captured, all the buildings are destroyed. As with units, buildings normally build at the end of the turn, but on the first turn build instantly. For building costs and functions check the genre pages.
There are five types of actions that existing units can take in a given turn (plus a sixth for SciFi).
Some SciFi buildings can perform actions. These orders are given similar to unit orders. Like with unit orders, some are instant and some happen at the end of the turn. Upgrade orders have a cost associated with them, which is listed in parentheses.
Besides Adventure, every genre has three global operatives who can each take one action every turn. Every operative has 7 possible abilities it can use. All operatives have 5 abilities in common which are listed below. In addition, each genre has a special ability shared by all 3 of its operatives, and each operative has its own unique ability. For information about operative specials check the genre pages. Adventure doesn't have operatives in the sense of the other genres, but instead has heroes which are units that perform many of the same functions.
Each genre besides SciFi has global spells that they can cast each turn. The resources required to cast depend on the genre, and some spells must first be researched as tech before they can be used. Some spells are instant, but those which are not get cast before combat takes place, but after units move or leave for attacks and raids. So for example if a spell is cast on an enemy province that kills units, it will hit units moving into the province and units defending the province, but not units moving, attacking or raiding from the province. Offensive spells have a chance to fail which is equal to the spell resistance in the target province. Spell resistance is 0% by default, but can be increased by some units and abilities. Spells which don't target enemy provinces are always successful.
Artifacts have a wide range of effects, but the most common are passive bonuses such as increasing resource gathering or improving your units in combat, or allowing you to cast a spell each turn. As a player, you have your own personal store of artifacts that exists outside of any game. This collection starts with 14 default artifacts but it can be grown by playing and winning ranked games. Any 12 of these artifacts can be brought into a game. Once in a game, your artifacts start unavailable to you. In order to use an artifact you must "find" it first using one of your operatives. Finding an artifact costs resources (the price depends on the artifact and is listed in its tooltip) and your operative's turn. Find is an instant action. Once an artifact is found, it can be freely equipped or unequipped at any time. You can only have up to 3 artifacts equipped at once, and you only get the benefits of equipped artifacts. Equipping artifacts happens at the end of the turn, but it's one of the first actions during rollover so any passive bonuses the artifact gives will affect the same rollover that it's equipped. Artifacts that have been found, but aren't equipped can be traded. Trading artifacts in game doesn't affect your out-of-game artifact collection.
Trading is one of the few interactions that happens in real time. You can open a trade with any player in the game. Things that can be traded are: the standard resources (gold, crystal, wood and ore), artifacts that you have found but that are not equipped, and diplomatic relations. Each player offers what resources or artifacts they would supply in the proposed trade. You can only edit your side, and not the other person's offer, so typically it's best to work out the details of a trade in chat first. Both sides can edit the diplomatic relationship in the trade. Once both sides of the trade are to your liking you can confirm the trade by clicking the "Accept" button at the bottom of the other player's side. If both players confirm the trade, it executes immediately. If any aspect of the trade is changed by either player, confirmation is canceled. A trade can also be canceled at any time, and all resources and artifacts are returned to their owners.
There are 4 types of relationships you can have with another player. All diplomatic relationships are mutual. By default you are at war with everyone else, but more friendly arrangements can be made through trade. For example, to offer an alliance with someone, open a trade with them and switch the relationship to "Alliance" and update the trade. Then click the "Accept" to confirm the trade. If the other player confirms, then you'll become allied. The four relationships are:
Knowing what your opponents are up to is an important part of playing effectively. Therefore every genre has ways of scouting enemy territory to find out what units and buildings are there. All operatives can scout a territory, some units have scouting spells, there are scouting global spells, and even scouting artifacts. Scouting reveals the units and buildings that were in a province at the beginning of the turn. The buildings reported are always accurate, but scouting is not always accurate about what units are present. How far off on the number of each unit type reported is likely to be is based on the accuracy value of the scouting type. There are also some situations where provinces are scouted automatically. The provinces of players who are allied with you are scouted automatically at the start of each turn while these relations hold. These scouts are perfect. You don't get automatic scouting information on players in a cease fire or at peace with you. When you lose a territory, it's automatically scouted since having just fought the army there, you know its composition. When you attack or raid an enemy territory, you see the army there, but don't get scouting information since there may be additional troops there that were built during the turn. However you can use your combat log to tell what units were there before recruiting took place. Finally, adventure automatically scouts all adjacent territories at the start of every turn.