with the map shown, press the big round knob.. on the right side of the screen you will have options to::
- change orientation
- save location
- scroll around the map (this process is not very user friendly, one of the few weaknesses of the RNS-E - most other systems use a joystick which works much better)..
this is a bad picture, but you can get the idea..
not sure if you can do it while guidance is active, but if not, you could stop guidance, save location, re-start guidance..