Hello Sedativand welcome to posting in these forums. You'll find many helpful people here and a lot of useful information. Make sure that you get the excellent User Guide too:
http://www.cockos.com/reaper/userguide.php
First of all, make sure that your keyboard device is configured for Input AND Control in Reaper's Preferences.
-- load EzDrummer and your drum kit,
-- go to the reverb and twiddle the knob you want to control,
-- if it is automatable (that is a plug-in parameter) then it will be listed as "last touched" when you click [Param] at the top of the EZDrummer GUI
-- if so, select "Learn" and the MIDI Learn window will pop up,
-- twiddle your keyboard knob / slider and it will be listed in the pop-up,
-- set the other options and click [OK].
Repeat for the other controls.
Full details are in the User Guide.