You can Customize 2 ways:

1)  Customize from scratch by hitting red CUSTOMIZE button above

2)  Find a decorated product and hit CUSTOMIZE DESIGN button on the right side of the page under shirt sizes

          - You can change the type of T-Shirt or product here by clicking PRODUCT on the top left of the page

          - You can change FONT COLOR by clicking on the box to the right of the Font type under Formatting