And now, the Newb presents... the Analysis Board
What has gone before: http://www.chess.com/blog/hop-along/bereshith
http://www.chess.com/blog/hop-along/and-now-the-newb-ii
So, you've got your game on and you're marveling at the beautiful interface. It really is - very intuitive and configurable without being cluttered. The "Analyze" option may give you pause. You click it and it duplicates the gameboard. Where's the analysis? It's in your head. Make the moves that you and (what you think) your opponent will make and see what happens. You can even uncheck the "Legal Moves" box and just make your moves to see what your position will look like if everything goes according to plan.
Don't worry. It won't.
One valuable lesson that I learned early on is that my opponent usually doesn't want me to win. Instead of making the move that would help me; they selfishly make moves that benefit their own side in the game. That took some getting used to. The analysis board helps you to see that devastating move that your opponent is about to make but your own eyes somehow refuse to see on the gameboard. The key takeaway is: when making your opponent's move on the analysis board - make the very best move you can. Their move will be better than that. Like I said, they're selfish. But, do your best.
If you do find a line you like on the analysis board. Make sure. Then hit the "Current" button to the right of the arrow keys. That will reset the board back to the "real" game but it will leave the move list filled out to however far ahead you analyzed. The last move in the real game will be shaded yellow. Select all of those moves from the "yellow" move to the last move that you analyzed. Copy (Ctrl-C) them. Close the Analysis window. Go to the "Notes" tab in the main interface. Paste (Ctrl-V) the moves into the notes field. Click the "Save My Notes" button. Now, you have a plan to work from.
This comes in handy if you get pressed for time or you forget what you were thinking. When your opponent deviates from your "plan" - ask yourself why. Did they make a better move than you imagined for them? Or did they fail to see the threat that you were planning? How can you best exploit their mistake or counter their threat? Is your plan washed up now? Pull up the analysis board and start again.
They were probably just being selfish.