Chris
You have to have 11 players selected to be able to score points. If any players you have selected are injured or suspended, that doesn't matter - but they individually will not score points. It is possible to pick one team and keep it for the season, but you are more likely to do well if you change players depending on form or who they are playing. The opp is the opponent/s they are playing next week, and if it says @ then it means they are away
at
that team's ground. No @ means they play at home. As the season settles in, you can sort the player lists by average points, and that helps someone who knows nothing about football to see who is doing well.
A useful tool is the current injury list:
http://www.physioroom.com/news/english_premier_league/epl_injury_table.php
Because of the salary caps, you may want to keep a star player if you bought them cheaply and they are not injured for long. This list is not always acurate, but gives a general idea of who is likely to play. I use the Sky Sports website each week to see the match previews, and if you are resourceful you might be able to pick up a suspension list from somewhere ;)