To confirm rvdborgt’s post, your pass is whatever you want it to be.
It is simply a fully flexible rail ticket and in no way does it set your itinerary or routing.
Obviously you need additional reservations for some trains, but the pass is valid on almost all trains operated by the partner operators. You can get on and off at any station of your choice even if you planned to go further, you simply add the next train to your trip and transfer to your pass. You can walk, drive, bus or even fly to your next use of the pass.
You can start wherever you like.