When you land on the landing page, click on "Let's add your photos". After clicking on the + sign inside the grey lined hexagon box you can hand pick photos from your device.
After creating, you can always make changes to your Photo Tiles, all editing options can be seen on Editing & Customizing.
In case you are all set to order, you can view more information on how to proceed on: How can I order Photo Tiles?
If you have any question, please don't hesitate to contact us!