Replacing the old Nexus Mod Manager is Vortex, a newer program for organizing your mod loadout.
Make sure you read the description page for each of your mods: many of them require specific steps and instructions. Once you've found some mods you'd like to try, here are the tools you can use to get them working. Go into your GPU software's control panel and make sure Skyrim is capped at 60fps to fix all that. The physics engine wasn't designed for it, and you'll end up seeing horses float into the air and bodies bounce around, as well as hearing loud, repeated sound effects as things like water splashes loop continually. The first thing you'll need to know if you're playing Skyrim on a modern PC in 2023 is that it's going to have problems running at a framerate higher than 60fps. That's why our guide assumes a manual pick-and-choose style of modding, and is sorted into categories so you can find a selection of individual mods that are compatible and suit your playstyle. It can be overwhelming to sort through all those mods, and installing a pre-canned list usually means adding a bunch of things you don't actually want, then not being able to get rid of them without messing up various dependencies.
Become a giant, fly, walk through walls, spawn any item you want, and even become Santa Claus with Skyrim console commands. There's no need to play Skyrim as a humble warrior.