It installs from the Android Playstore, as do most Android apps, with a "desktop customised" version. Better than Chrome in several ways, especially privacy - separate password vault, cookies reliably deleted, etc. However, we could do with a separate help page because many tweaks for Android simply don't work in ChromeOS.
In particular, I'd like to hide the side menu bar for more screen space .Opera say "Alt F11" but there are no F-keys on a Chromebook!