Well now, how to install it? Just follow these steps bellow:
1. Login to your facebook account
2. Click this url --> http://apps.facebook.com/fansectiongames/commish/nfl/
3. Click "allow access"
4. After that choose your own league or you can create your own league. Then click Join the league
5. Then, you will be asked to fill the form to create your team name and logo, see the picture bellow
Note: you can upload photo from your computer or just select your photo shown bellow the browse tab
7. Now you can invite your friends to play the Fantasy Football or just skip it you don't want to invite your friends.