Since it's a web-based browser, you must access it using the IP address:Port number URL. By default, File Browser uses port 8080, and it should easily load after installation.

If the Documents app feels a bit overwhelming, try out the File Manager & Browser app. This is an ad-supported file manager that provides all the basic features for free.

This is an open source, browser-based tool that can convert the most common image, audio, video, and document formats. It isn't clogged with ads and you don't need to create an account to use it.

That’s going to change soon as Google is going to integrate a file browser right into YouTube Music, which will allow you to play your locally-stored files without having to exit the app.