Please Help Someone Who Understands The IPhone

Hello, I will drive directly and I will try to ask my questions in the easiest and most correct way possible, although I am having difficulty due to lack of knowledge in the field. I recently found out that on the new iPhone models or maybe on the new version of iOS it allows you to quickly turn on a new phone, through the Backup option, which should transfer everything from the old device to the new one (photos, phonebook, apps, etc.) however, they are: I'm currently using an iPhone 7 and I want to do the Backup in question on a new iPhone Xs, yes, but as far as I understand this happens with an iCloud account (I don't know if that's the case, you'll tell me) and I've been using one for a while Apple ID account for all my devices, which are about 5-6 in number, so I'm worried that if I activate iCloud (which I don't use because I don't understand, everything goes wrong, various photos and applications climb into my other devices, etc.) this is exactly what will happen and all my things will go wrong. If I create a new Apple account and then Backup the new iPhone Xs, will I be able to transfer only all the information from the old to the new TVDon without confusion and if possible without involving iCloud, although as far as I understand this Backup is via iCloud . Well, this is one of my questions, and in general, if someone can explain to me in a simple way what to do, what to activate, as well as not, etc. and so on to transfer all the information, I will be grateful! I watched the videos on YouTube, I didn't understand much, because I'm not good with English either, please save me the hate, I don't understand, that's what I'm asking here. The other question is, if I successfully do this Backup what does it do with the old device, do I turn it off,