[Yuusuke]

I'm a little confused using both.

Can someone break down both of these so I can understand how it works.
Also How can i put these in negative form?

Lastly, How do you say "you must do this" ex: you must take of your shoes at the genkan

and how to say "it's okay to" ex: "it's okay to use a fork"

ありがとう
　　　　　　、幽すけ