Best way to arrange your products properly is to create some categories and subcategories through which your clients can find the matching products. These categories will build up your menu in the end.
It is that easy:

1. Hit "Products > Categories"
2. Enter the name
3. If you want one category to be subordinate to another, you can simply select this under "Parent category". 
4. Click on the matching category and subcategory when creating a new product
5. Don't forget to save the changes and you are finished :-)