GERMANY quarantine question

We are already in Germany and have not been in any of the high risk areas (Zurich & Dusseldorf) coming from Vancouver, Canada 7 days ago.
However we would still like to do a test on Monday when we are in Munich and are planning to do so at the airport as we would like to enter Austria and maybe Slovenia.
While we are quite confident that it will be negative, there is of course no way of saying if we did pick it up somewhere despite of all the precautions.

In case that the test result comes back postive, how would the 10 day quarantine have to be handled? Can we book a hotel of our choice and stay there for the duration?
Just want to be prepared for the unlikely case of unexpectedly being positive.