For cleaning, the gun manuals explain everything you need to know. For ammo, take your pick and experiment. My advice below should take a back seat to whatever your manuals say.

A .22 lr rifle and a shotgun have different care. After every range session with a shotgun, I field strip it, clean the bore, spray CLP around, and rub stuff down. An 870 is not delicate. So, I don't have to keep everything flawless.

For a .22 lr rifle, I field strip it, but I hardly ever clean the bore. When I do, I don't try to get it looking like a mirror. I read somewhere that you're not supposed to clean the bore on a .22 lr rifle often. Apparently, it's easy to mess it up by cleaning it too much, or even by cleaning it a little.

For oil, I'm not picky. I'll use CLP, Rem Oil, motor oil or whatever. I haven't found much of a difference between oils. I've read threads where some people get worked up about which oil they use. I haven't used anything terrible yet and haven't had any rust. So, I don't have any reason to get worked up about any oil I've used.

Last but not least, if you have utilitarian guns like mine, then you hardly ever have to clean them if you just want them to work. I personally like my firearms to be clean when I put them away. I'm generally a clean person overall.