For Blue Player: Hold Shift (you won't be able to move while you pressed it) then press A or D. You'll shoot and have a small waiting (for balancing purposes) before you can move/shoot again.
For Red one, the same with the delete and the arrow keys.
Archers have that waiting time and can only shoot left and right for balancing which makes them not too much overpower. In an Ideal game, archers keep being a good option cause they don't attack the castle with melee so they avoid the 1 damage from atacking, so they needed some disadvantages. I also made the soldier able to resist 2 arrows and yet attacj the castle once so you have another viable option against archers (as they don't do any close combat damage)