1.First the mouse has to find the key. When he gets the key then it will help him to eat the cheese. 2.When the sprite on the bottom left corner turns to blue colour, it means you are far from the key. Yellow colour means you are a little close to the key. Red colour means you are very close to the key. 3.Press the arrow keys to move.
I give my credits to Da_Kool_Aryaman.