It’s easy! Challenge streams start about 30 minutes before the challenge at livestream.com/mxcoriginal , then, at 8 minutes before the challenge I run a little guessing game where I pick a number based on the number of people in the chat. Whoever guesses closest to the number gets to decide who or what cannon thing gets drawn.

Then, maybe 2 minutes before the top of the hour, I post up a picture of the subject matter being drawn and everybody that wants to draws for 30 minutes(If anybody keeps the livestream on I play music).

At the end of the 30 minutes I open up the submission box at http://my-little-art-challenge.tumblr.com/submit , and leave it open usually for a good 22 minutes so that everybody has time to put any finishing touches onto their drawings.

Hope this helps!