Help me clean my database by following this tutorial

Can someone pls help me do these steps from this tutorial:

https://blogsuccessjournal.com/blog-tips-and-advice/wordpress-tips-advice/seeing-weird-characters-on-blog-how-to-fix-wordpress-character-encoding-latin1-to-utf8/

I don’t really understand what to do in STEP 4,5,6,7, can u please tell me where should I run those commands? I tried in phpadmin, putty (using root) and non worked lol.

Any ideas?