I suggest you could try belwo steps to host a reasct app on the IIS.
If you don't have the react app, I suggest you could install the npm and generate a react app for testing.
1.Open cmd and locate a folder by using cd yourfoldername

2.Run below command to add the package
npm i -g create-react-app
3.Run below command to create the react app in the folder, wait for creating the application
create-react-app my-app

Build the project to production folder.
npm run build

5.Open IIS management console and create a new web sites and use the build path as the physical path. for example: D:\ReactAppTest\my-app\build
Notice: You should pay attention to your port number.

- Then you could use that port number to access your react application. For example:
http://localhost:9965/
