How to test
Discovery is not available until you set the connection as live and visible so that users do not get offered options that are not ready to be used. To test your connection you will need to use debug mode to make the connection selectable by you.
Once you have tested and are happy, you can set the connection as live, visible and optionally default then save. This will make it live for your users within a few seconds.
Multiple connectors and OpenAthens accounts
This type of connector is best used as the default connection. In this mode when a user arrives at our authentication point with your organisation known, such as would happen if they select it at at a resource's login, use a WAYFless URL, the Redirector or have previously authenticated successfully, they are passed directly to your login without seeing our authentication point.
If you have a need to use multiple connections, or OpenAthens accounts alongside local accounts - e.g. if you have a group of users that are not in your directory - then you can set the connection as live and visible but not default and set it to allow OpenAthens accounts via the setting on the domain preferences page. In this mode when the user arrives at the authentication point with your organisation known, they will initially see a chooser where they can select the connection to use - all live and visible local connections will be available as well as an option to use OpenAthens accounts. The authentication point will remember their choice.
With multi-valued attributes - e.g. the memberOf field in ADFS - the interface is not able to display all values and only display one. All values are read and cached though so are available for things like permission set rules and attribute release.