How do you make train reservations in Germany if you are using a Select saver pass?
If you go to the Deutsche-Bahn website, you can make seat reservations.
Reservations are optional on most daytime trains within Germany. You can make them at any train station for about €4 or as an e-ticket on the DB web site - check the box for "reservation only" as you start your ticket search. Some international and overnight pass holder fares are not sold as e-tickets online.
A seat reservation is actually 4,50€. A family reservation (parents and their own children) is 9€. For that fee, you can get reservations for two trains in one direction. That is, for example, if you are reserving a connection from Munich to Köln with a change in trains in Frankfurt, you would get reservations for both trains (if they are express trains) for the 4,50€.
For the ICE Sprinter, such as some of the ICEs that go non-stop from Frankfurt to Berlin, a seat reservation is mandatory and included in the full fare ticket price. A seat reservation only on that train includes a surcharge for the premium train and costs 11,50€.