Take a look at the rescue mission included with the huey in the mission editor, they (the troops) are broadcasting over VHF FM. In that mission set your FM radio to home and which ever freq you need. So in practise, the troops in that mission are broadcasting on 40.5, set VHF FM radio to 40.5, set transmit receive switch to home (4 clicks clockwise), use the Course deviation indicator (on the dash) for navigation using the VHF FM method.
If you are navigating to a NDB (not sure if you can add these in a remote location) tune the NDB frequency into your ADF radio and flip the switch to ADF, use the Magnetic compass homing needle for navigation.
The manual is vague on the use of the radios and navigation. I'm in the process of writing my own radio use manual, all this info I had to figure out on my own and internet documents on the real radios because of the lack of detailed info in the manual.