edit libreelec setup file

hey
I created a .tar backup file with the built-in LibreELEC backup tool.
Is there a way to edit that file so I can add some addons to it?
Extracting it is no problem, but how to get it back to .tar format (readable by the LibreELEC restore tool) on Windows or MacOS?

Best regards

Quote from chewitt

There's already thousands of pages on the internet that explain how to use tar so to eliminate PEBKAC issues it's probably easier to stick with the GUI tools in Kodi. So: Restore the backup. Install the add-ons from the Kodi GUI. Take a new backup. Job done.

then please please show me one of those thousands of pages, I can only find info on how to create .tar.gz archives...