Sorry, I didn't see this message before. If you mean How I got the cursor on the screen to cast spells, it's a bit of a hacked together solution, using some scripting and some eventing.
I found a way to stop events and the camera (as well as limit the character's movement to what's in the camera when I stop it) through scripting. Then I found a way to put a sprite on screen on command (so that we have a "fake" protagonist on the screen), I turned the graphics for the player to the cursor, and I made it so that "flagged" events can still be interacted when I stop events. Then it's just a matter of eventing the rest as normal (you are effectively just controlling the protagonist as normal, and I track which spell is selected with a variable).