Database help

I recently purchased the Dynamic Suite Dynamic Suite, eCart, DataAssist, SecurityAssist, Universal Email
I am having a problem comprehending the process of setting up a database that will work properly. I have read the material provided, watched the tutorials, and searched the internet but still cannot grasp the organization I will develop with my tables.
I presently have a website designed in Dreamweaver and have purchased the Dynamic suite so we can sell direct to the customer.
We are selling 2 items. A crew neck undershirt and Boxer Brief. I would like to have one page for each item and be able to give the customer a color choice and size choice, the price will change according to the size category
My color choice is white or black.
I would like 3 drop down menus for size. One for regular size, one for big sizes, one for tall sizes. I followed the info you gave to someone else where color and size are in the OptionGroup table. I am now lost about what step to take next. You mention about listing the combinations in the ProductOptions table. It appears that I will not get a combination with both color and size as they are in the same table. Should I have a separate table for color and one for size? Also in the ProductOptions table do I need to list the combinations? Can you show an example of how to fill the table? I am trying to get on to actually using the extensions but can't get past the database. I wanted to add that Lands'end has an option where the customer first selected regular, tall, big, and big/tall. Then the drop down menu shows only the sizes available in the size range you choose. I am trying to avoid 3 separate add to cart buttons on the same page. Then I would also need the price to adjust. Your help would be much appreciated.