Welcome to the world of chess.  I played quite a bit when I was younger but not much in the last 20 years.  Do you know about the analysis board?  Under the moves tab next to the message tab you will find the analysis board link.  This board will present the current game and allows you to make moves both yours and your opponents.  You can try many scenarios before you go to the real board and make your final move.  Of course it's not a good idea to become too dependent on it because you won't have one when you are playing someone face to face.  A book on basic chess strategy and some opening examples is a good bet.  I'm sure there are some beginner lessons on the net but concentrate on lessons on the basics of strategy and openings.  Good Luck