Make updates and changes in our own APK

This is a job that needs to be done quickly. Within 3 days. Please read properly and don't waste mine or your time. We have for the past two years developed an APK for restaurants together with a freelancer. However, he can not continue anymore developing and we are looking for someone to continue where he left off. The system is up and running and used on a daily basis. Cautioness is very important to not affect daily operations. Developed in Android using Google firebase. [Summary of the APK] There is two APK's, one is "ADMIN" and the other one "MENU". This is a system used for restaurants to make ordering digital. When a guest arrives the waitress use her admin-apk to occupy a table for the guest. The waitress also receives a "table code" which is handed for the guest. The guest later needs to type in the table code when they fullfill their order. The guest is then handed a tablet with "MENU-APK" on where they can browse for food, desserts and drinks and make their order. Once an order is made it goes straight into the kitchen where they use the "admin-apk". [Function of admin-apk] * Waitress table - Used for the waitress to occupy/unoccupy tables for the guests. * Incoming ice cream - Shows incoming desserts and ice cream in kitchen. When a new order has arrived it has the status "New" - when the chef/staff starts working on that order the press "new" and it changes to "process". When chef/staff has finished the order they press "process" which now changes to done. The waitress now get notified and can go to kitchen to pick up the dessert to deliver to guest. * Incoming food - Shows incoming food in kitchen. Also works in the same way with new, process, done but for food. * Incoming drinks - Shows incoming drinks in the bar. Also works in the same way with new, process, done, but for drinks. * Orders overview - Shows an overview of all incoming orders, food, drinks and desserts/ice cream. * Admin (within admin-apk) - Here I can add food, desserts, drinks etc. * Pending cash orders - Here the waitress can see which tables wishes to pay with cash and can adress them. * Survey - After the guest makes their order we have a short survey and this is where I can add/change questions. [Function of MENU-apk] Here the guest can browse among our food, drinks and desserts. They press a "+"-sign to add the item to a cart and can then choose to pay with cash, card or SWISH (Swish is a Swedish local payment option). [About the project] I need to add a few new functions and also change some present ones. Below is a short summary, and I've also attached documents with presentation and details about the functions. [Changes to present system] 1. Disable table code and use table number. 2. Change payment flow, guest now pays in advance, want them to pay after they get their food. 3. Add colors depending on status for watiress table map 4. Be able to tap "delivered" in overview (admin-apk) 5. Add "Paid/not paid" to overview to easily see which tables have/have not paid. 6. Be able to tap "all" incoming drinks instead of individually [Addons] 1. Function for guest to add extra ingredients to their food. 2. QR discount system. Be able to apply discount to a guest with a QR-code. Freelancer only allows 4000 characters so I have to stop here, the rest of the details are in the attached word document.