I've written a couple of blog posts about shame that you will need to take time to read in order to understand/do this challenge. These outlines the explanation of what shame and your "shadow" is as well as my own experiences on thoughts on the subject.
It's All the Shame
The Shadow Effect: Acknowledging My Dark Side
Your shadow is your shame. All the stuff you replay in your head. Your regrets. Your mistakes. The things you punish yourself for over and over again. It's everything from your deep dark secrets to the stupid thing you just can't believe you said that's constantly playing on a loop in your head. This is your time to forgive yourself and set yourself free. Stop hiding in the shadows. Acknowledge that you have a dark side (as does everyone else) and don't just forgive yourself, EMBRACE it! Make it part of who you are.
The movie "The Shadow Effect" talks about how you can't have light without darkness. Once we stop trying to push down all those parts of ourselves that shame us and, instead, assimilate them into who we are, we are then free to fully embrace all that is wonderful about us.
Face what shames you today and decide that you are STILL enough. Then step into the light.