Running Combat
Nice swing! Note how your character's AP has dropped. It takes 28 AP to attack with the club. If you have 28 or more AP, you can attack again.
Once you have too few AP left to attack again, you will need to press the Spacebar or click the "End Turn" button in the bottom right of the screen. This will end your turn and give the Orc it's turn.
Don't worry; the Orc shouldn't give you much trouble. End your turn, then wait while the Orc takes its turn. Your turn will then come up again. Continue attacking and using the "End Turn" button when you run low on AP until you defeat the Orc.