Code doesn't autocomplete/isn't colored

Hey,
I created a little custom crafting custom item but nothing works
I'm pretty sure that I copied everything 1 x 1 from a tutorial ( https://www.youtube.com/watch?v=s8p-V1TWE1o&list=PLv1bCaEzD6z3UpL7ElpcaXWvm0VfULik6&index=6 ) 
and at that part he is able to choose from many options, while I can't do anything...
Do you know how i can make it work?
Would be realllyyyy great <3