To use, import this module into your ~/.xmonad/xmonad.hs:

   import XMonad.Actions.FindEmptyWorkspace

and add the desired keybindings, for example:

   , ((modMask x,                xK_m    ), viewEmptyWorkspace)
   , ((modMask x .|. shiftMask,  xK_m    ), tagToEmptyWorkspace)

Now you can jump to an empty workspace with mod-m. Mod-shift-m will tag the current window to an empty workspace and view it.

For detailed instructions on editing your key bindings, see XMonad.Doc.Extending#Editing_key_bindings.