I'm sorry, i'm a little bit confused about the best way to create an new application. My initial thought was to define some classes first, then give them an GUI and datastorage. But I can't find a way that strataframe is providing me with the tablestructure/sql needed for storing the class. Instead it's prompting me to locate an existing table from a database. But that's not what i want, I want the tool to generate that new table for me, not using an existing one .

am i missing the point or just the way to do this ?

If you want to create a new table, then you need to create a structure in the DDT (Database Deployment Toolkit).  This is a tool that allows you to create SQL structures then map those structures to the business objects.  You can then take those structures and the DDT will deploy those structures to SQL Server for you and create all databases, tables, indexes, relationships, stored proceures, etc. for you.

The tutorial is designed to show you how to create an application once your data structures exist, which makes sense since your application revolves around the data structures.  But you can step back and create a DDT package which will then create these structures for you and also allow all of your mappings to be pulled from that meta-data as well.