If you’ve created a new account and generated an api key I think you just need to go Billing —> overview and setup your payment method.
I think you get $20 credit for signing up after that and your key is active.
Edit - the default model will be 3.5 as well. I think you have to request GPT4 access still. But they’re giving out access pretty quick these days I think.
Edit 2 - Actually it looks like GPT4 should be available from the start as well now. Nice!
Not currently unfortunately, I just started work on adding PaLM API support in some form.
I’ll have to look into LLaMA after that is complete, I hadn’t even thought about that one yet haha.