GameMaker has a great number of ways in which you can move instances around within your game room, ranging from setting speed and direction vectors to simply "placing" an instance at a specific position, as well as using more sophisticated methods like path-finding. There are also a good number of different methods for detecting collisions between two instances, and which you choose will depend largely on the type of game you are making and the exact situation that you need to use the collision functions in. The following sections cover all of this and list all the functions related to movement, path-finding and collisions: