This simple algorithm shows how a player wins when catching a mouse:
Mouse spawns near the player. Player chases the mouse. Player catches the mouse.
Now it's your turn.
Expand the algorithm to show that the player starts with five gold coins, receives a coin for every mouse caught, and loses a coin for every mouse that gets away.
There is no wrong way to do this. It's an exercise to get you thinking about how algorithms can be broken out into steps to solve a problem or accomplish something.