After the panels have been created you also have the function to clone them. For instance, if you were creating a shelf. Just click on the clone button and select the face that you would like to offset the shelf from. You are also able to edit the value of the thickness of the panel. It, might not necessarily be the same thickness as the panel thickness of the cupboard.
Once you have created your shelf you can then do further modifications if necessary like mitre or trim.
Just as an aside, the use of parameters will greatly assist in the design process when quick changes need to be made as well as better control of the model.
For instance, if you look at the picture below you will notice that Thicken1, 2, 3, 4 and 5 all have a value of 18mm. This is the value for the panel thickness. If I wanted to change that panel thickness to 16mm I would have a lot of work ahead of me of selecting the cell and then editing the value. Very, very tedious. If I had created a User Parameter (panel_thickness) and linked each value when creating the panels all I would need to do to change those values was change my one User parameter and all the panel thickness values would change instantly.
In this example below, you can see that Thicken 6, 7, 8, 9, 10 and 11, the equation for the value is Panel_Thickness. Changing one value in this situation changes the value of all your panels.
