In Rise, Left-click selects a unit. If you have a unit selected, left-click an enemy in range to order your unit to attack them. Attack orders are marked with a red arrow. Attacking units will move automatically.
Right-click on a hex in range to order a selected unit to move there. Move orders are marked with a white arrow.
During the draft, each time it is your turn, you select a unit and then select one of the highlighted hexes to place it in your army. Select it again to remove it.