Each week you pick one team to win its game. If you are correct, you survive. If you are wrong, you get one strike. Three strikes and you are eliminated.
To make it somewhat challenging, you can only pick a team once during the season, so sooner or later you will have to pick a dud team.
It is simple to register. I never use my yahoo email address except when registering at sites where I am not sure if I want them to know my citytel address.
Because of your post, I checked my Yahoo account and found out that last year I missed out on $10 from a poker site I no longer use.