The map below shows where in Oslo NOTAM is situated, and below the map there is a description of how one can get there.
The address is:
Sandakerveien 24D, Bygg F3
Using the bus is the most convenient way to get to NOTAM by public transportation. Bus lines 20, 37 and 54 all stop in Arendalsgata in Sagene, right at the westernmost end of the bridge “Bentsebrua”, below which we are located.
If you want to travel by tram, there’s a stop in Vogtsgate along routes 11, 12 and 13.
A good overview of the buildings in the Myren area can be found here.