As for connecting it all you have to do is do a menu restart and when the lights go off on the front of the unit pull the power cord. That is the safest way to do it. Then connect the eSATA cable to the external drive and the HR21. Then plug the eSATA drive in and let it start up. Then plug the power cord to the HR21 in and it will start up and be ready to go. Leave something recorded on the internal drive so when you boot up with the eSATA drive you can make sure your "My Playlist" is empty so you know it is working correctly. As for drives that work I don't know. I do know the WD My Books do not work on DVR's and the Seagate Free Agent Pro's do not work on the HR21's.