The gameplay is really simple, you can move once every turn (unless you have multi move perk). If you want to enter combat mode, select your card -> pick your target -> hit the play button. The damage will depend on ur card's rank and hand type will affect the multiplier.
You also notice the card's suit? There are 4 different kinds: "Suppression, HE, AP, Chemical (basically toxic)" which will also apply the effect to the target (❁´◡`❁)