Greasy Fork

How do I load a script into Tampermonkey?

I'm not even a novice at this. I've used only one user script, Mondo Pita, but it broke upon some OS update months ago. I have Tampermonkey installed on my MacOS w/Mojave 10.4, but cannot get it to accept the Greasy Fork phpBB User Hide engl script. Apparently I need to type something after _@ include _ in the script to tell it what phpBB I want it to work with.

1. Is that correct? If so,
2. What do I type in? and
3. How do I type it? (I can highlight it but can't type into it)

Thanks. And remember ... there are no dumb questions, just ignorant inquirers.

Wow! I guess that's a tougher question than I realized. Maybe that's why no How To tutorial I've found yet has worked.

!