Grief Prevention commands not working

I recently started my own SpongeForge server running forge 1.12.2 and sponge. I am running luckperms, and nucleus additionally. However when I try to run any commands considered part of grief protection, it says that no command exists. The weird part is that luck perms allows me to assign perms to different groups etc. so the only issue is that I can’t use the commands.

GriefProtection is no longer being developed or supported.
Look up GriefDefender, that is the same dev but a new and improved plugin

Do you know how to turn the zip file from github into a jar file?

If you means the source code, then you need to compile it (assuming the licence of grief defender allows you to do so - you should check). If the code is already compiled then change the .zip to .jar (a jar file is a fancy zip file)