I would recommend using this documentation Backup and Restore
A powerful, but user-friendly Backup and Restore tool provides an easy way to use pg_dump, pg_dumpall, and pg_restore to take backups and create copies of databases or database objects for use in a development environment.
Using the pg_dump utility, pgAdmin provides an easy way to create a backup in a plain-text or archived format. You can then use a client application (like psql or the Query Tool) to restore a plain-text backup file, or use the Postgres pg_restore utility to restore an archived backup. The pg_dump utility must have read access to all database objects that you want to back up.
The Restore dialog provides an easy way to use a Custom, tar, or Directory format backup taken with the pgAdmin Backup dialog to recreate a database or database object. The Backup dialog invokes options of the pg_dump client utility; the Restore dialog invokes options of the pg_restore client utility.