Enter dimension if you have an item in your inventory

I'm making a dimension that can only be entered if you have an item in your inventory. If you don't have it, a message appears saying "You're not ready to enter here yet."

The problem I'm having is that I don't know how to use returns in procedures and I'm having trouble finding information on how to create a procedure that sets conditions for entering the portal.

This is what I have:

https://imgur.com/a/z1PCchR

I know it doesn't make sense to put 2 identical returns inside and outside the if, but I can't find a null return or something like that and I don't know if it's correct.