Points can also be awarded to defensive teams or players depending on if you draft defensive teams or players. You can also add in other statistics. For instance special teams score points when they score a touchdown. If your league drafts individual defensive players, give points for tackles, sacks, Interception's, and fumble recoveries. Now that you have your scoring system, now you have to set a number of players for the roster and also how many players are going to be starters.
Starters are the players that actually get points for the week.
You can add or take out anything you want. You want TE mandatory, fine. You want 2 or 3 QBs that's fine too. Play around with it and do what you want. Normally you will want the roster to have twice as many backups as starters so that each team can carry a back up for each position.