TV Platform Studio - How to add custom plugin to add download button at bottom bar?

Hi All,

I am adding TV Platform Studio on my website page. Now I have a requirement to add a download button on player which opens a html popup and it takes information from user, on submit it should starts download.

I have tried to search in document and forum both but I am not able to find any good example or article to start with. Can anyone please guide me on How Can we create custom plugin to add button on bar?.

Thanks in advance