It simply says complete it to get the loot. Contest Terms
“Complete . . . . to receive one Blueprint Master Badge and one Unreal Engine SWAG pack”
But there was some issue with registration. I remember signing up but I never got a start reminder or completion email.
“After registering, you’ll be notified via email when the challenge officially starts”
“Participants who earn the requisite number of Badges for a given Reward will be notified by Epic”