I have been preparing videos and manuals for testnets since the first time. You can find all the guides I have prepared on the link below.
https://github.com/okannako/subspacenetwork
Guide and video for Gemini-3f.
https://github.com/okannako/subspacenetwork/blob/main/gemini3f.md
https://www.youtube.com/watch?v=i7OKHcqE5Rc
Thank you