Compression test? There is no way you will get any kind of meaningful reading by rotating the engine by the crank bolt. A total waste of time.
If I may suggest...
Go to the library and get a book on basic four-cycle engine mechanics and maintenance/service and tune up procedures. It may shed some useful knowledge on things in general.
Also, you should have the BMW Bentley (pub.) manual.
I'd buy it in a heartbeat... if only I wasn't living on the moon!