Reimport project into library

I just had to reinstall my Windows. So I made a backup of my Unreal Engine projects and copied them back after reinstalling Windows and Unreal Engine.
How can I reimport them into my library now?
Of course I can open the project file but it is inconvenient.

Hi KnitterX,

If you open the Project Browser by launching your editor, you should be able to browse for the project in question. Once you do this, it should automatically populate in the project browser for future use.