In a snake round each pick is one minute apart. In an auction method each pick can be 20 seconds apart. Your roster is made up of all of the players on your team, including both the lineup and bench players. The entire league should have no more than 180 NFL players. Otherwise the free agent pool is too diluted.
Trading is one of the main parts of the game that keeps the game exciting and competitive.
The bench is the players you sit that week. You have a bench to hold onto players so other teams do not take them. You also have a bench for players that are on bye during a week. Every N.F.L. team has one week off a season. Some leagues use IR so that valuable lineup and bench spots are not taken by a player that is currently injured.