Entering to win is relatively simple, provided you're attending SDCC or know someone who is. All you need to do is visit the Xbox Gaming Lounge at the Manchester Grand Hyatt, where you'll find all of the exclusive consoles up for grabs, and tweet a picture of your favorite using the hashtags #XboxOne and #XboxSweeps. 20 people will then be selected to win an Xbox One and accompanying Kinect.
If you're not able to make it, there is an alternative way of entering which involves mailing your entry info to Microsoft. Full details on how to do so are outlined here. Additionally, a Nerdist-branded system will be given away online through the official Xbox Twitter account.