Select “design your own” from the menu.  Then select “customize” on the image of the type of product that you what.  Select the color and size at the bottom of the screen.  Now you can add text and images to your design.  Make sure that you position the artwork where you want it on the product.  When you are happy with your design, click the “add to cart” button and your order is placed at My Sister & i.
NOTE:  Use the save button (see example of the icon below) on the design screen to SAVE your design for future amendments.