Do we have to book or can we just show up ? Is there a line ? How does it work when we get there ?

Better to book ahead

You should book ahead

You have to book previously to ensure a space. There are specific times for entry. It is very easy to do online.

I was told we needed to book but we had a 2 groups of 10. If you're a single or double I'd call to check.

From my experience, you should book. There wasn't a line, because of the reservation system. Once you get there, you check in, they give you a waiver to sign, then you're in. There's a proctor/observer, just in case