The app only has a single pair of user credentials (defined by the admin during installation). Have a look at https://docs.minio.io/ for further usage instructions (all steps regarding download and execution of minio can be skipped, as this has been taken care of by the app itself).
In its default configuration the app may require you to open up additional ports in your firewall, since MINIO is currently exposed on port 8345 (for HTTP) and 8456 (for HTTPS). These ports are automatically configured in the UCS firewall, but may need to be added to external firewalls.
Additionally, some redirects inside the app are configured to the DNS name of the UCS host the app is installed on. Please make sure that the DNS name of the UCS host resolves properly.
Alternatively, it is also possible to define a custom hostname and SSL certificate for Minio. In case a custom hostname is configured Minio will be available through the Ports 80 and 443.