When you check your handy work, the engine will need to be at TDC. You use an opening on the transmission to line up a mark on the flex plate or fly wheel to set TDC.
If you have an automatic trans, here is how to set TDC:
http://newbeetle.org/forums/750427-post1.html
On that page you link to, they have a manual trans where the port you use line up for TDC is at the top of the trans, but the photo shown on that page is worthless because it doesn't show the 2 alignment marks.
Anyway, once you get the belt together, roll the crank over 4 full turns and back to TDC and make sure your cam marks line up and the timing belt tensioner is set correctly as well.
If you've never done a timing belt before and you don't have the Bentley Factory Repair Manual for your car... you're gonna have a bad time.