Yep, Pucks got it.
In a nutshell for easy maintenance, each week you are sent emails from the NFL Fantasy league giving the status of your pre-selected (by draft) players. You simply make sure that the player you have, for say, the 2 QB positions your team carries, are both playing in the upcoming week (No BYE week). You confirm your roster and the outcome of the game does the rest. Points for how many yards, TD's an offensive player has. Defenses are a total of yards allowed, points scored, and Special Team scores. Its really very simple, I was intimated by FF for years until me brother in law convinced me to join a league. Takes about 5 minutes of your time each week to maintain your league, or you can spend endless hours researching players and doing trades with others, or putting your less-than-expected players on the Waiver wires and picking up new players to replace them.
If I'm not mistaken, you get something like:
1 QB's
2 WR's
2 RB's
1 TE
1 Kicker
1 DST (team defense and Special Teams)
The points they produce week in and week out affects the results that your team produces.