I have made a database backup using odoo's database manager facility with the older Bitnami instance. After setting up a new AWS instance with the new Bitnami image, I have made a restore of the dump-file with the mode "Copy of an existing database".

That's all.

I think it has to do with the "Name of the Database". I've done it both ways and can't tell the difference.

In my opinion its just a matter of understanding ....

Restore data:
If the table you are to restore currently exists at the same location, (note that it has not been dropped and recreated since the time the backup was taken) you would make a restore.
Copy data:
          You would make a Copy data in when the table does not currently exist, when the table had been dropped and recreated since the time the backup was taken and if you want to make a copy of the table in a different database, other than the one in which it exists.

       Might be little bit confusing but it is based on your need.