How Do I Make the Most Out of My Kobo eReader?

I got myself a new ebook reader for Christmas! It's a kobo of precisely the right size, and so far I'm loving it. It has a wifi connection and an experimental web browser, which appears to be it apart from the ebook reading capabilities (which supports many formats, and is not locked to a store of any kind).

Does anyone have tips on how to get the most out of it? Is it possible to install third party apps? Are there any good ones?

-- CC0 ew0k, 2021-12-25