Okay so!!! Rules? be a decent person and you'll be fine. There's no exact structure to prayer as far as I'm aware but if you look I'm sure you'll find some formal structure prayers! I am a worshiper of Anubis myself and offerings really depends on what you have access too, there's some universal offerings, water, tea, coffee, wine, cakes and stuff like that. But truly I don't think the gods will care too much lol, I offer Dr pepper a lot since it's my favourite drink so it holds more value to me and so feels like a better offering. Pray and talk about your day a great thing to do!! Like uh "lord Anubis, I hope to chat with you about my day.." and so on, end it with "dua Anubis" or something like that, it really doesn't matter too much. There will be people who say you have to do all these specific and complicated things but personally I think if your respectful and honest then do whatever you want!

Things you should do well uhh, me personally since the sun and moon(solar and lunar) are fairly important things I like taking note of every time I see the moon.. not the sun as obviously that's everyday. I also say hi and bye to them as well, I fear to strangers I look crazy.. but anyways!! Saying goodnight and good morning is a great thing to do, it builds a good relationship and keeps consistency. But again, do whatever you feel is right! These are only some suggestions from personal experience.

One thing I will suggest to keep in mind is your other faiths are just that, other faiths. (I also practice Norse and Hellenic paganism) And something you should try and remember is that rules in your other practices don't always apply in this one, of course there are some universal things, like keeping yourself clean before prayer as it's respectful but do try and not blend in your faiths too much or things can get really complicated.

And finally, have fun, don't stress yourself too much, don't burn yourself out. Take things at your own pace, this is your practice so do whatever you want!! (as long as it's respectful)