So I am sorry I am so new at this but here goes...

I am a red sox fan and wouldn't mind picking up a few game worn jerseys of guys I grew up with (Rice, Evans, Hurst, Stanley, Boggs, etc.). Here is a Bruce Hurst jersey for sale on Ebay:

http://cgi.ebay.com/Bruce-Hurst-1985...ayphotohosting

How in the world would I go about authenticating this. What am I looking for as far as tagging, etc.? Is there a guide out there (preferably free) that could get my started). Also, your opinions on this listing and what makes it legit or not are appreciated. Thanks!