I didn’t use the system in Germany, but as a casual observer I think their system works something like this: The bike spaces are numbered, and the passenger has a reservation ticket with that number on it.
All bike spaces on
IETs▸ are numbered and have a reservation/available display.
The passenger needs the carriage letter on a reservation confirmation to know which carriage to head for.
The storage areas on each train that are the designated cycle spaces need to be more clearly marked as such to lessen that chances of prams and luggage being put in there.
TM‡'s should have a quick and easy method of checking at which station(s) booked cycles will be boarding and alighting.