Not sure where you can hear the sounds, but I'd try youtube or a similar site for a video of a GG-1 or EP-5 equipped with Railsounds 4.
Once ERR is installed, DCS will see and treat the unit as a TMCC locomotive. Follow the instructions in DCS to add a TMCC locomotive and you'll be all set. There may be additional instructions in the ERR manual about setting the cruise commander settings and such, but this can all be accomplished through the DCS remote.
-John