You can access your PostgreSQL databases using PHPPgAdmin. This application can be found on https://phppgadmin.ulyssis.org. To login you need to use your PostgreSQL password, this password is different from your account password for security reasons as well as convenience. In case you've forgotten your PostgreSQL password you can get it from your websites configuration file. This is usually called config.php, wp-config.php, settings.php or something similar.
You can login by clicking on the only server in the left sidebar PostgreSQL voor gebruikers, kringen en organisaties. Once you've logged in, you will see an overview of all your databases. You can then view databases, schemas and tables by clicking on them or navigating through the sidebar. For each table you can view the records, view and change the structure, add records, take backups, etc. Official documentation of all functionality is sadly lacking, but you can still refer to the official documentation
To take a backup of all your databases you simply select "Export" on the main menu, define whether you wish to export data, structure or both, and press export. You can later restore backups by uploading the file to the "SQL" page. To make restoring easier, we suggest however you backup individual databases or even individual tables and use the SQL format instead of COPY.