for anyone else who ever needs explicit help for my original problem,
Here is the solution:
in YaST, in the Software category is already selected by default. Click on the Installation Source icon.
You'll notice that your CD or DVD installation media is already listed. Disable it .
Then add these 3 URLs separatley:
adding these 3 repositories will be the same as if you had the 5 installation CDs inhand.
thanks to Niclaus for the help: