Too bad I missed this, making candy is a major hobby for me.
As someone else pointed out you don't have to have the marble but it's prefered because it helps the sugar mixture cool quickly. You CAN use a cookie sheet but LIGHTLY oil it first and set it on top of a grill net so that air can circulate around it and help cool it. Also, don't use a non stick pan because when you start working the fondant you might scratch it and those fine little pieces will get in your candy.
FYI, if you want to know when the candy is done and ready to be kneaded just put the top of your hand over the mixture -- do not touch it, once you pour it be very careful not to disturb it for any reason or it will crystalize -- and when it feels pleasantly warm then you can start to work it.
Also, do not scrape the bottom of the pan when you're pouring and know it's okay if you don't get all of the candy off the board into your ball. It's better to be safe than have a ruined piece of candy.
Enjoy the process, it's fun!