How do I make this type of mod?

[Hooski]

I want a mod that spawns a character on specified levels that chases you, I would also like adjustable options in the menu.
Specifically I just want Baldi to chase you like in the game. I want 2 things for be adjustable in the menu, Baldi's slap speed and if when he gets a player if its an instant death or just damage.

I feel like this entire thing sounds a little weird i wrote this when i was supposed to be sleepin

i want to learn how to code this myself i dont want someone to do it for me
but it would be nice if i had some real help aside from random youtube videos

 

[binqillin]

I don't know if there's a way to import player-like characters unless if you rewrite the whole movement or just do a bare bones for the movement