Whether this is your first time, or just a refresher - Welcome!  
Our goal here is to point out the most important, and most useful information for ZCS newbies.  Please read the rules for more detail, but here are the most important points for you to remember.

1. Be courteous!
2. Schedule your matches by using the email form!
3. Make sure your email account works!
4. Watch the deadlines for playing and posting matches!
5. Only post wins against matches you played!
6. No Cheating!

Be courteous!
Common courtesy is expected of all ZCS players.  This doesn't mean you have to chat up a storm with your opponent - it means to be aware of your opponent and treat them as you would want someone to treat you.  Consistent bad behavior (overly criticizing your opponent, or the dice, consistent insults or cursing, leaving a match before your opponent has a chance to save a match when they request it) can be grounds for removal from the tournament.

Schedule your matches by using the email form!
You can reach the email form by going to the brackets page and clicking on your opponents name on the left hand side of the bracket.  Copies of all emails are sent to the host, so that way - you can be sure that you have documented your attempts to schedule a match.  When the round is over, forfeits will only be considered for those players who have used the email form to schedule matches.  MOST IMPORTANT - use the email form during the first week to schedule your matches.  Otherwise, you may not be entitled to a forfeit at the end.

Make sure your email account works!
It is your responsibility to make sure that you have provided a working email account, that can receive the ZCS generated emails.

Watch the deadlines for playing and posting matches!
In addition, if you have won a match, then you need to post that win within 24 hours of the match.  Otherwise, you risk being DQ'd.  Plus, you must have played or made an honest effort to play, all your matches.  This is where the email form comes in - the host will see if you have made an attempt to schedule your matches.

Only post wins against matches you played!
Sounds simple, but where this really makes a difference, is IF your opponent, says they aren't going to play, so just post a win - DON'T!. It's against the rules.  If you have been found to deliberately post a win that you didn't play, or tell another player to post a win against you that wasn't played, it will be considered grounds for being DQ'd.

No cheating!
Using any outside assistance, including other players, bots, printed dice tables, is considered cheating.  Taking advantage of a defect in the backgammon program that causes your opponent to have lost a match that they didn't really lose, is cheating.  Any player found cheating will be DQ'd from the current, and (at least the) next ZCS.

And a few other tidbits...
Screen Capture - There may be occassions where you want to capture what's on your screen as a record of what happen. There's a good tutorial at Aunties' that may come in handy (click here).