Install the extension using standard Joomla! installation procedure (Extensions -> Install/Uninstall).
After installation, Art Adminer can automatically be used to connect and manage your Joomla site database.
Click the blue settings button to launch the settings modal.
Next, select 'No' where it says 'Connect to Joomla DB' and click save.
After the settings are saved you will be prompted to enter database credentials for the database you would like to connect.
Click the blue settings button to launch the settings modal. Then select which Style you'd like to use and click save.