1. You cannot create a studio when you are a new scratcher.
2. You can still comment and make projects when you are a scratcher.
3. To become a scratcher, you must keep making projects and comment.

It's really nice that you want to help out with a guide! However, we have a number of them in the forums already and we don't have a good way to showcase any more. If you want to make a guide in a Scratch project, that would be fine. You could advertise it in the “Show and Tell” section too.

There are lots of other ways to help out in the forums too. Helpful Scratchers are always welcome in the “Questions About Scratch”, “Help With Scripts”, “Requests” and other sections. Just look around and ask questions