by Dani Palou.
Hello,
the documentation you need is in the point "2.1 Enable authentication for sites using SSO methods (like Shibboleth and CAS)" of that page. Basically, once you install the plugin you just have to configure the authentication via browser (embedded or not, as you prefer).
Please notice that in Moodle 3.2 this setting was included in the core of Moodle. So if you're using Moodle 3.2 you don't need the plugin to do this, you can configure this going to Site Administration > Mobile app > Mobile authentication.
Kind regards,
Dani