How to hook up a subwoofer with an integrated amp?

Hi Audiogon community,
Thank you in advance for your help.

I have a Plinius 8100 integrated amp and would like to connect a subwoofer.
Also, any sub recommendations for a 12X12 room? Looking for a musical sub for 2 channel listening.
My speakers are RevelM106.

Here is a link to the manual:
http://www.manualslib.com/manual/131213/Plinius-8100.html