If you're just getting started, then go here and get KoboldCpp. It will run quantized models without installation.
If you want the best fast models, you want mistral 7b models. There are a bunch, but my favorite is Dolphin 2.1 Mistral 7b. It screams on a potato, and it's output is second to none.
Start up KoboldCpp, point it at the Dolphin file, and you should be good to go. I mean, there's a tiny bit more to it than that (picking your GPU and context settings and so on, but it's pretty easy).