At the beginning of every turn you will collect a certain amount of troops. The number of troops you get is determined by this formula:
(regions ÷ 3, minimum of 3) + zone bonus + spoils bonus
"regions" are the total number of regions you occupy.
"zone bonus" are bonus troops you get for occupying all of the regions that make up a zone.
"spoils bonus" is the number of troops you get for playing a set of spoils.
What's a set of spoils? You earn spoils at the end of every turn in which you successfully conquer a region, just like reality! These spoils each represent a region on the map and can be blue, green or red. If you acquire 3 spoils of any one colour, or one of each, you now have a "set" of spoils which you may exchange for additional troops at this time. The value of these spoils depends on which spoils game option was chosen: escalating or flat-rate. You also get a 2 troop bonus on any region that you own if it is represented in the set.
You will place your troops on any regions that you occupy. The game will ask you for the name of a region, and how many troops to place there, and will continue doing this until all of your troops are deployed. Once you deploy troops, there's no changing your mind, so give this some thought first!
You may now assault any opponent's region from one of yours, as long as both regions are adjacent and your assaulting region has a minimum of two troops. This part is optional in that you may choose not to assault anyone.
Each time combat is initiated, the game engine will roll a die for each troop involved. The outcome is determined by the dice of the assaulting troops versus the dice of the defending troops.
The more troops involved on either side, the better the chances that side has of winning. But not all troops in the regions are necessarily involved. To be more specific, the game engine will roll a die for each assaulting troop, less 1 troop that stays behind, up to a maximum of 3 troops. Likewise, the game engine will roll a die for each defending troop, up to a maximum of 2 troops.
The outcome of combat is determined by comparing the strongest dice of either side. If the assaulting die was higher, then the defending region loses a troop. If the defending die was higher or equal, than the assaulting region loses a troop. This process is repeated once more if other troops remain involved on both sides.
If you destroy all of the troops in your opponent's region, you will then have to occupy it right away by advancing some of your troops (but not all and at least 1) from your assaulting region to the conquered region. If you conquer a player's last region, (thus eliminating him/her from the game) the former opponent's spoils become yours!
During this part of your turn, you may assault any adjacent regions, as many times as possible, until you decide to stop. For example, you may assault one or more times from one region, switch to another region and then back to the original.
When you are finished your assaults, you may reinforce your defending position. If desired, you may move some (but not all) of the troops from one of your regions to any connected region which you also occupy. The Reinforcements game option will determine how many of these reinforcement plays are allowed.