Okay, so I could do this myself and all but I better go to sleep and see if someone already knows what it is all about.

So:
Launched up Hammer, everything's working as it should, no problem there. Thing is that I don't have a clue how to make checkpoints. I'll provide screenshots of what I am working with in the google docs:

https://docs.google.com/document/d/12TnI7yzYdY1YWrQJIJnurLzx4oTA9bCbPn-B5Pw7D0E/edit?usp=sharing

for more context, I only assigned outputs to triggers and for the gmod_runfunction I changed its name to HitCheckpoint and nothing else.

I am probably making a very small error somewhere or just missput some stuff so I'll be very happy if someone's willing to help, thanks. I can provide more description if needed.