The help is coded in inverted Morse code:

PHYSICS IS THE TALLEST
CHEMISTRY TWICE ON THE RIGHT
TANK IN THE FOREGROUND

The sketched place is about 160m east of C6.3.

The second puzzle was an SMS puzzle: simply press the given keys while you are writing an SMS and you get HUT BEHIND PORCH SEVENTY M NE.

The place is an old shooting range, also a location of a geocache.