Sales App for Alluminium & uPVC Doors Windows

We want to create door window selling, producing, transporting & installing App. The app shall enable user/customer to download it and design his/her own door window ventilators as per their requirement and generate a quotation instantly. After the design they must get a clear picture of the product they will get on confirmation. Once the confirmation is done through initial part payment, the owner company shall allocate a installation engineer for the job from the data pool of all certified installation engineers available with it. The installation engineer will visit the site of the customer and certify the openings suitable for window installation as well take final measurements of each openings where the confirmed door window ventilator are required to be installed. The app should enable to record these details. After authorisation by installation engineer the company will allocate required material and generat production documents on it's own separate software for the production and installation of the required products. Production will take palce in two stages at different places. The first stage part production will take place at Mother plant, where in suitable profiles will be cut, milled, routed, reinforced and packed to move it to second stage Baby plant, nearer to customers. The second stage production will take place at Baby plants involving welding of the corners of all units, corner cleanings of the units and then assembling of the different parts to finally give shape to the doors windows and ventilators. After the production of the products the installation engineer will arrange the products to move to the site and get it installed by certified installers. The intended app requires to record each and every steps involved in the process and ensure step by step free and fair communications to the stake holders. As the products are made out of either Aluminium or uPVC the landing page of app should enable to opt for the base material and then the customers are directed to feed details of the each openings like width and height of openings, sill width and height, lintel height, location of the opeings etc. Also the opening picture can be captured for better judgment by the designers. The app should be handy for the operators to understand the different options available, its prose and cons and suggestions from the experts. The app should give clear idea of the prices, taxes and terms of the deal before finalisation and confirmation. The confirmation should happen only after varifications of the required material at stocks of the Mother plant. Before final confirmation the app shall enable signing of legally binding supply agreement.