ecomers app

hi, I have this project. I need to connect fully functional back end to a new front. all of the information is in this link https://drive.google.com/file/d/1eH7QfGf759R6VxgDEVAs1mrt5g2kuaE9/view?usp=sharing budget is 500$. if you can do this for me I have a lot of other work.
this is the working app today https://play.google.com/store/apps/details?id=com.app.meatapp