Thank you for your response, Chris.
I am very new at this, and I think I am getting the terminology mixed up. As it seems I can create a database using "phpMyAdmin" which is included with MAMP and runs on my Mac.
I guess what I need to do is create the tables, like the sample one provided with ecart. The sample table (or I think it is more than one table) is combined in a document with a file name ending ".sql". It is this document I need to create and then import into my own database.
Thanks to a very good book "Dreamweaver CS3, the missing manual" I was able to create a Database, import the sql-file and connect it with Dreamweaver.
Am I making sense?
Could someone point me into the right direction how to create an sql-file?