Como Puedo recuperar mis archivos de mis mapas?

To get the last time you did Check in Changes on them,
Close UEFN
Go to your User/Documents and Move the Fortnite Projects folder to somewhere else on your hard drive.
Open UEFN
Should see the download icon on them like BOX FIGHT 2V2 in your picture.

Any missing ones you can move the individual Projects folder back to the new Fortnite Projects folder.