The rules for patch admission vary from rink to rink, but they usually ask people to have a minimum level of certification to go on - at my last rink you had to have passed Skate UK 8 unless you had a coach with you, in which case you could be any level - however you'll find that the enforcement of these requirements is often lax at best and the kids on patch are rarely following most of the patch rules themselves. They usually want you to have your own skates as well, which I assume you do have.
The reality of patch is you only really have to be aware of the people around you and be able to get out of the way, which you've said you can do. The main other thing to be aware of is if someone comes flying at you in a hi-vis jacket as they're probably practising their programme and technically have right of way. That's pretty much it though. My last rink had some hilarious other rules like "no jeans" and "no talking", but those were never enforced further than a coach telling you to stand by the barrier if you wanted to chat for a bit. They also had this hilarious archaic rules about always giving way to skaters of higher level, but that appears to have been adjusted to skaters of higher level being expected to work around lower level skaters, though I did always try to get out of their way.
I think a lot of people think transitioning to patch will rid them of the pains of things like hockey skaters, but the reality is that patch can be literally as messy and chaotic as public is and the kids on it are just as unaware of their surroundings as most public ice skaters - even if they know you're coming then they still often rabbit-in-headlights regardless. Therefore, if your session sounds quiet then I'd heartily recommend hopping on if you feel comfortable and your rink will let you because a quiet session will be easy to manage and you'll actually get to make use of it compared to a busier patch or public session.