Is there a reason you can’t paint over the black wall paper? That would probably be the easiest way to cover it up with the most efficient coverage!
If you cant paint, some other temporary options are removable wallpaper or a tapestry! If you can’t make holes in the wall, Command hooks are great to hang tapestries on! Etsy has a lot of great options for removable wallpapers, and Urban Outfitters has a lot of tapestry choices!