All instances in GameMaker: Studio have certain "built
in" properties that you can use and set to govern how they look and
behave. speed is one of those properties and defines how
many pixels the instance will move every step. Unlike hspeed and vspeed, speed has no direction
associated it with it as this is governed by the direction value of the instance, but
it can have a negative value, in which case the instance will
travel in the opposite direction to that set by the
direction function (ie: direction - 180°).
if keyboard_check(vk_up) speed = 2; if
keyboard_check(vk_left) direction += 5;
if keyboard_check(vk_right) direction -= 5;
The above code will use the arrow keys to set the speed and direction of the instance.