I need to make a React Native App responsive

I made a very simple react native app, and it looks good on my phone, but when i run it on another phones it does not appear to be good. I need someone experienced with react native to make the design responsive and looks the same on all devices.
This project is very simple and easy, and will not take too much time. My budget is $10, please do not bid if you wont work within this budget.