Adding a button to an existing react app

Hello, so I am using the react app provided by this git link, GitHub - jitsi/jitsi-meet: Jitsi Meet - Secure, Simple and Scalable Video Conferences that you use as a standalone app or embed in your web application., and I want to add an additional button to the toolbox and due to me having no React Experience I have no clue how to start. Does anyone have/know of a comprehensive guide, I can use to help me?

I have gone through this page many times before but I couldn’t figure out how implement a button with a new function that I add since I could not figure out the html file, or the file that produces the html of the toolbox within the files in the git link from the OP
image

the image here I edited using paint, for I have no clue how to implement this with the code provided

The code is here: jitsi-meet/react/features/toolbox at master · jitsi/jitsi-meet · GitHub
You can see how other buttons are implemented.

So I was attempting to implement a button that just changes the icon on said button (so like how the icon of the videomuting button changes upon click) so to if I use the VideoMuteButton.js within the components folder in the link you provided what parts are necessary?

You pass toggled: true to the ToolboxIitem as props

So I have did all of this and build/make the app, but I didn’t see a new button appear. Which files do I have go to to add the location of the new files I made somewhere else to make the button appear? I ask since this seems to me what I am missing