If you're a React beginner and just getting started with the React. You must have tried looking through the documentation and specifically the "Intro to React - Tutorial".

If you haven't already I would suggest you to go through it because it is a really nice and quick way to get started with the library. https://reactjs.org/tutorial/tutorial.html

But there are a couple of questions that this tutorial leaves for you to solve as practice and again I would highly recommend you to solve these.
Once you have given it a try you can go through this github repo that I have created with detailed explanations (checkout out the README) to all these practice questions. Hope you find it useful. Have a good day!