Please also refer to the NBI Vistors Pages.
On the above map, the arrow indicates the HEHI building (T). The hatched areas indicate some lecture halls (auditoriums). The cantina is in building F, the reception in building A, and library in building C, the rest is offices and the like. What isn't shown on the map is that most of the buildings are connected by underground passageways.
The map above shows the area around NBI. The blue dot marks the entrance to the reception. The HEHI building is in the next courtyard. Note that there's a bus 3A stop (Irmingersgade) just outside NBI. You can use Rejseplanen (public transportation) or Krak (car) to plan your route to NBI.