How to Make Affidavit of Liability?

This could just be me being a dumb teen, but how do we get an affidavit of liability? I read in the rules for the contest “Find Your Star” that we need to present an Affidavit of Liability to claim any sort of prize, but my mom doesn’t know what it is and isn’t really helping me out, and any website I go to only tells me what an affidavit in general is, and not how I can make one.