No question is a bad one if you really don't know the answer and you really want to know!
Many people will respond but:
In order to utilize a keyboard with reason, it must have midi capability.Hook up you midi patches via Midi or USB, whichever setup you have. (I say USB because the many midi controllers have midi/USB capability)
Select your keyboard under preferences/Midi/etc..... Then get to experimenting. that is where you may return for more assistance.
REDRUM can be programmed to run on it's own after you select the different pad on different channels. Or you can click the Redrum line on the sequencer until the midi icon appears, that makes that track active,then you can control Redrum via your keyboard or whatever gear you may have.
Sorry if I confused you, I don't have Reason up and running to verify. Somone else will probably break it down better, but I figured i'll write something in the mean time that might get you jumpstarted....