How to insert create-react-app project into existing python/flask app
A rough outline would be:

configure the build folder to be the folder where static files are served from by your server (js, css, ...)
include the files from that folder in the template of the page your want your react app to display (via <link> and <script> tags).
render a container in the same template that react can mount on.
We have an existing python/flask app (made by someone else) that has a nav bar, sidebar and different pages. We have built a create-react-app project that we want to sit on one of these pages in the python/flask app.
The question is - how can we integrate our react app into the existing python/flask codebase?
Any help gratefully received!
Update: from helpful answer below - could anyone help with explaining this a little more - perhaps with code examples? "render a container in the same template that react can mount on."
Update 2: Someone else suggested "You can have React run anywhere where you can add a script tag into HTML and a DOM element to attach it to. As long as you have a way to bundle and serve the JS files, you should just be able to include your new app like that." - could anybody help with code examples of this?