This should just be as simple as installing the native app, and installing the web extension. With both installed everything should work as expected.

I would be more than happy to help; however, I need to collect some technical details. Please open an issue on GitHub and I will assist:

Client Issues:
https://github.com/cssnr/hls-downloader-client/issues

Web Extension Issues:
https://github.com/cssnr/hls-video-downloader/issues