I've seen many different streams, but I don't know how to make one. How?

On your profile page there's a tab that says "My Streams"

Click that, inside that page should be a "Create Stream" button.

imgflip.com/create-stream

Let me know if you have trouble after that.

Thank you!

Making the stream is half the battle. Getting people to sub to the stream is the other two-thirds ;)