When you create an instance, you can create a TEMPorary variable. This will save the ID of the instance created to that variable. You can then set that instances direction and speed by editing the variables
direction and
speed prefixed with that variable in dot notation. Maybe you can even target that variable, I don't remember. But to explain dot notation, if you don't know, let's assume you made the temp variable
bullet. You would set speed and direction of the bullet to the shooter's image_angle like so:
GML:
bullet.speed = 4
bullet.direction = image_angle