Welll, you're kinda barking up the wrong tree in this C/ to begin with.
But, your question, while not actually stupid, is also not the right question without a lot Mir more info.
Style wise? There's no real styling on lemmy. You make a banner, and you're done, pretty much. If you can't cobble together a banner between gimp and/or canva, you really aren't ready to learn anything that would help you make a great banner. There's a certain ground floor when it comes to designing something really nice, and if you can't use the most basic tools, you're essentially asking someone else to do it for you. Not that you'll never find someone, but it's a big ask.
As far as modding goes, you shouldn't learn that from one person, ever. Yeah, it can be nice to have someone to ask about the tools available on lemmy, but you don't need a teacher for that, just head to whatever the lemmy help page is and go ham.
If you're wanting a co-mod or mods, isn't [email protected] a thing? Or am I misremembering the name? Anyway, if I've got the name wrong, there's a place to request mods to help out somewhere, and if you can't find it on your own, you aren't ready to run a community on lemmy anyway.
But, before you go asking for mods, you'll want to be able to explain what the C/ is going to be, what rules you intend, and what policy/ies are going to be in place for moderation. Nobody is going to volunteer blind. Well, nobody worth having most likely.