I recommend starting off with the Nexusmods, since its the easiest to use and doesn’t require much “access” like some other sites. There is alot of diffrent sites to use for this. Just when downloading the mod or checking the requirements tab under info it will say the requirements and provide you with a direct link by pressing the name.
Theese are usually the requirements, i wont tell you how to install them but it’s easy to look up yourselves. Of course mods require other mods, that’s the way it works. Tho i recommend if you are starting off with Vortex you will most likely need to watch a few videos on how to set it up and use it to it’s full potential. There is also the old Nexus Mod Manager but i wouldn’t advise using that if you want to really get into heavy modding.
There is alot of diffrent ones out there, but the one i prefer for the moment is Vortex.
This is where it can get a little tricky, you will need to choose a Mod Manager to use.