Quick Guide to Managing Your Team

You can manage your team by logging into the NFL site and/or the NFL Fantasy app and going to My Team.
As a team owner you can do several things to effect the outcome of your team and most of these things can be found in the My Team section of the site

Adjust your roster by moving people between the bench (BN) and your active line up.
Add players from the list of players that weren’t chosen by anyone in the draft. This group of unclaimed players is called the “waivers”. You can’t have more than 15 players so you will probably have to drop a player to do that.
Trade players with another team in the league.

Waivers - Players that aren't on another team in the league

Any request to add a player off of waivers is processed on Tuesdays and it’s done in inverse order to the teams’ standings. So if the worst team in the league and the best team in the league request the same player, the worst team gets the player.
There are certain players that most experts agree are going to be so good that, if they are on your team, you can’t drop or trade them without permission from me/the rest of the league. This keeps someone from making mistake or getting into shenanigans (i.e. tanking on purpose)

You can continue to mess with the players on your roster until those players’ teams kick off that week. The season starts this Thursday night when the Philadelphia Eagles play the Atlanta Falcons at 8:20pm. After 8:20 on Thursday you will not be able to move any Eagles or Falcons you have on your roster until next Monday. You get or don’t get whatever points they score or don’t score in that game. You can continue to move around the rest of the players on your roster until their respective real life teams kick off.
There is normally 1 game on Thursday game, a bunch of games on Sunday, and 1 game on Monday night.
Each team gets one week off during the season. These bye weeks start happening on Week 4 and are staggered so only a handful of teams have off on any given week. You will not earn any points for a player on a team who has a by week.
Football is a rough game and most of the players on your team will miss more than a bye week due to injuries. Be prepared to have a backup in case of injury.
I will end with this, many of your current players will not do as well as you hoped or any of the experts thought. There are also players that no one drafted who are going to have a breakout year. This is where the fun of fantasy football comes in; Finding that diamond that no one has noticed. I have won a couple of leagues and normally finish in the top 3 but hardly ever finish the season with anything close to team I had at the beginning.