Now in order to install the mods themselves - make sure you read the specific instructions - but the gist of it should be as simple as copying the mod files to the main GTA 5 folder. asi plugins, while Native Trainer is the thing that lets you access cheats like teleportation, super jump, and more.
Asi Loader is essential because it allows you to launch. Do the same with both dsound.dll (this is the Asi Loader) and NativeTrainer.asi.If it does, we'll update this guide, but you're stuck with vanilla GTA 5 until then. Unfortunately, Script Hook V hasn't been updated to support the Epic Games version.
If you're playing the game through Steam, this can be found in \SteamApps\common\Grand Theft Auto V\.