I wanna make it so that when I click on this machine in Oak's lab, it brings up a separate screen with pokeballs where I can choose my starter
I've seen other hacks such as GS Chronicles do this:
https://imgur.com/a/xOAARnE
And it's also a similar concept to that used at the beginning of RSE:
https://imgur.com/a/ndopsqZ
So how could I enter a similar script into my game?
I know this requires creating a new special command then calling that special in my script, but I have absolutely no clue on how to do this.