Flutter App modification

mobile app written in flutter. currently 1 customer and 1 owner app. single owner multiple stores setup, i wish to change certain features. To change to a , multi-vendor, multi-store setup. has chat functionality, in-app notification push, and in-app wallet. current features 1. single owner 2. multiple stores. 3. Current customer app, displays all stores in various geo-locations 4. multiple category and products are plublished under their category but belonging to 1 owner. changes-Vendor app -------------- 1. multiple vendor app. Change the current single owner app to a vendor app, where multiple vendors can manage their products. 2. each vendor is registered under a store. therefore multi-store, multi-vendor app. when a store is clicked, it opens all the registered vendors to that store. and when a vendor is clicked it opens all the items the vendor has for sale. 3. 4 buttons added to vendor app -get loan -get insurance -Delivery Service -manage my inventory/book keeping 4. integrate book keeping and inventory management 5. Add In-app chat application, allows vendor chat with customers users 6. Add in-app wallet function to vendor app. customer App ---------------------- [login to view URL] page currently displays all the stores in their geo-location as well as items sold. However front page should now display geo-location stores as well as, featured traders. 2. customer can click store, and this displays all the vendors registered under that store. 3. customer can click on specific vendor and see all vendor items for sale 3. customer can chat with vendor 4. customer can register for premium service. 5. add ads module Laravel back-end 1. add mobile ads module-allows admin load video, graphics to display on customer app and trader app. 2. see list of traders 3. see all loan request 4. send in-app notifications to particular customer groups or vendor groups