What they are explaining is different from the normal scenario.
I know how to assign an effect to a track. This is different. It starts out the same, using a send on the track you want reverb on, but that send goes to the AUX channel with the reverb club in (as it normally would) , whose INPUT is the APOGEE FX buss. Then the output of the AUX channel is muted, and the same send as on the original track is put also on the AUX channel. You control the amount of reverb with the Apogee Control software. Works in Logic and Pro Tools, just not here apparently, since AUX (Group) channels in Cubase have no input available to assign. It would probably work if the Apogee FX channel could be chosen as a send from the original track (therefore acting as an input to the FX channel, but that is not a choice in the “SENDS” dropdown.