No you're not being dim, the RFL website isn't that helpful!
As for level 1/level 2 it really depends on what age/level you're wanting to coach at.
I'd suggest the best way is to do the level 1, coach at kids level for a few years as a no.2 to somebody else then do level 2 and then coach where you want.
Though I don't think there's anything stopping you from going straight to level 2 if you want to, I did but then that was 10+ years ago so it might have changed.
IIRC Level 1 is a 2 day course that covers the basics of being a coach (preparing/delivering a session, risk assessments etc) and is aimed at kids level coaching. It's very much the first step into coaching. If you've done coaching before you should sail through it quite easily, if not then it might be a valuable course to do.
Level 1 allows you to coach but I think you've to be under the supervision of someone with a Level 2.
Level 2 is the "standard" amateur coach level, it means you can coach at any level up to the professional leagues.
It does (or used to anyway!) cover the coaching basics but also goes into player development, long term athlete development, laws of the game etc. IIRC it's a 4 day course.
As I said, I went straight in at Level 2 but whether you can do that now I'm not sure but Level 1 might be a good starting point anyway. I think the Level 2 course costs around £200 so I'd be looking to help out at an amateur club and get them to pay your course costs rather than paying it yourself!
I'd highly recommend giving Sam Horner at the Leeds Rugby Foundation a bell or drop him an email and asking his advice as he'll know more about the current courses/requirements etc than I do and he, along with Leon Crick at the Foundation run the Leeds Rugby Coaching Association who deliver regular Coach Education classes for amateur coaches in Leeds.
Sam Horner -
sam.horner@leedsrugbyfoundation.org