To run this map, place the .bsp in 'Steam/steamapps/common/portal 2/portal2/maps'

then start a coop session and as host write 'changelevel mp_coop_tabav1.1b' in the console

more detailed instructions at:
http://forums.thinkingwithportals.com/mapping-help/playing-portal-2-custom-maps-t4076.html