I need to make an application that a potential client can download for free from my web-page and use to design his/her homepage (with e-business) from a fixed set of design themes, and when finished, upload the pages to my web-server.

The solution must be fully data driven (selecting a different design theme should alter appearance, not text) and must also be able to upload inventory and download orders at the clients request.

The server must run processes to support the e-business solution.

How should I go about putting it all together?