Anyone know how to load backups?

So I accidentally destroyed my survival world, and need some help recovering it.
Got back into singleplayer minecraft recently (good distraction from the stress of exams), and have been just vibing in a peaceful survival world. Mostly just building stuff and mining. In my haste to log on and play the other day, I didn't realize I was logged in to my brother's account. He plays on the latest version, 1.18.1, while my world is played on 1.17 (the latest version when it was created). I only realized my mistake when I saw his skin's arm instead of mine, and he started getting advancements in chat. I quickly left, and tried to re-log on my account. It warned me that since the world was played in a different version, it could be corrupted, so I made 2 backups. I figured that it would be fine, but no. Everything is gone. My whole island was deleted from existence, and I could see all my animals drowning in chat. The world saved too quickly, and nothing I did fixed it.
I can't for the life of me figure out how to load my backups. I downloaded WinRAR like it told me to, but I have no idea where to go from there. I'm not super tech-savvy, and it's really confusing. Can anyone help me? I really don't want this to be the end of my world :(

 

You can load a backup using the following steps:
Right click the windows button (if you use windows, idk how to on another operating system) and click on "Run". Then type %appdata% and hit ok.
Then open your .minecraft folder and go to the "Backups" folder.
Then find your world and simply unzip the file and put it in your "Saves" folder (which is also under .minecraft).
That should load your backup, assuming you did in fact make one.
Hope this helps :)

 

where should the backup appear when I boot up the game? followed your instructions, but so far I don't see anything different. should there be a new world? will the old one just be fixed if I load it? the old corrupted world still has the red 'outdated version' text underneath it. do I have to put the unzipped file directly into the old world's save file?

 

You should just have to extract/unzip the backup, and place the folder in your saves folder (you may have to rename your backup). Then yeah it should appear in your normal world list when you reload the game.

 

alright, I'll try re-naming it. thanks for all your help!

 

No problem, hope you got your world to work. Glad I could help :)