From: koln
To:
Dresden
There is a one direct train at 09:05. Also the cheapest ICE to Dresden. But not the fastest connection.
All other connections will require 1-2 changes.
The fastest connections have a change at
Frankfurt airport train station. With 4 tracks rather small. And a rather new station with lifts, wide platforms, same level of the platform and the train doors (no steps), etc.
I suggest you look at this links you might find some useful information,
transportation and
things to do.