Digital showroom

I would like a digital showroom like [login to view URL] or [login to view URL] No milestone. 50% payment after 50% of job is compete and i test it and the ather 50% after the job completed. I have already a Joomla website and i want to put it in the Joomla website. I would like a demo first and then i give the job. I have all the backgrounds images. I send 4 pictures. The 2 first is the background and the ather 2 is the color i want to change for the background. It is 3 different themes with 4 background pictures per theme. Also every them has 11 different colors. I have the color also. I want also to can add background pictures or themes in future by myself. Also be responsive.