I put in some of my own textures as backdrops but I cannot see them. What am I doing wrong?

Be sure that you put the textures in at least the control box and the upper canvas.  The mid and lower canvas will just show black (white for the wedding edition) if you only drop the textures into the control box and upper canvas.  If you want them to show for all 3 parts of the canvas, also drop them into the mid and lower canvas sections.

Solution

You MUST use ‘edit linked parts’ to drop your textures into the canvas pieces.

1. Go into edit mode. by right clicking on the control box and choosing Edit from the pie menu.
2. On the edit window put a check in the ‘Edit linked parts” box.
3. Now click on the control box.  It should be the only object highlighted.
4. Now click on the ‘Contents’ tab in the edit window.
5. Drag your custom textures from your inventory into the contents area. (Hint use your SHIFT key to select several textures from your inventory so you do not have to move them 1 at a time.)
6. Now repeat steps 3 though 5 for the upper, mid, and lower canvas section.
7. Once you are done, close the edit window and click on the upper canvas or use the arrows on the control box to cycle through and you will see your custom textures.