Not sure about those impulse files, so try starting out by downloading these
Lexicon 480L impulse f8les - good stuff. A zip file, doesn't matter where you put it but with your samples makes sense to me - of course, you have to extract the zip. Then, in Reaper, add Reaverb to a track. Click the Add button, select file, and browse to the directory wth the desired reverb impulse. Would suggest turning off "normalize impulse response". Hope this helps!