There are two types of units: Kings (K), also referred as armies or monarchs, and Knights (N), also referred as fleets or horses.
Each type of unit moves and supports according to the adjacency they would have in chess.
Powers can build in any owned supply center alongside their first two rows. For example, the Ottomans can build anywhere between A1 and A7, or between B2 and B8, as long as they own the supply center in question.
There are no retreats: all dislodged units are taken off the board.