Launching the setup installs unconfigured firefox (?)

Hi, first of all this is my first time cloning something from github since I'm not a programmer and not much of a power user so this might be (probably is) a mistake from my part but since I have no one with the knowledge I hope I can get a answer.

1. I've installed git, cloned the directory into a folder (using git clone --recursive https://gitlab.com/librewolf-community/browser/windows.git)
2. Once downloaded I get the folder "windows" and inside of it I have the powershell script and a .exe file named 7za that I still don't know the use since when I execute it nothin happens.
3. After executing the powershell script I get this

Remove-Item : Cannot find path 'C:\WINDOWS\system32\firefox.exe' because it does not exist. At C:\Users<myusername>\Documents\Librewolf\windows\package.ps1:2 char:1 Writing web request Writing request stream... (Number of bytes written: 10406064) + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.RemoveItemCommand

Remove-Item : Cannot find path 'C:\WINDOWS\system32\librewolf' because it does not exist. At C:\Users<myusername>\Documents\Librewolf\windows\package.ps1:3 char:1

• Remove-Item -Path librewolf -Force

•   + CategoryInfo          : ObjectNotFound: (C:\WINDOWS\system32\librewolf:String) [Remove-Item], ItemNotFoundExcept
   ion
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.RemoveItemCommand
  

4. Once finished I get a firefox.exe on the windows folder, but it is simply the normal installer. After installing I get the vanilla Firefox with no changes whatsoever.

Once again, I'm probably making a mistake somewhere but I'd really appreciate some help with it.

Thanks.