HttpService to automatically promote people in a group from a game?

I've read and watched videos on HttpService and I'm still super confused and I don't know where to go from it.

I've seen Get requests and Post requests and JSON, but it's all a big jumble in my head. I don't clearly understand what each of them are and what they do.

Do I have to connect to roblox's proxy, roproxy.tk?

Do I have to create a domain on a web host?

How would I change a rank on the ROBLOX website in a group?

Hello, you would need a website (or someone else's) Then you need to make or get a hold of a "HTTP" script, that uses the exact request, and add a user (alt) in the group that has promote/demote power) not sure if you need an alt, depending on the site and script.

More than this is hard to say, only two people has made such script i think.

Then how would it be possible?