This is an old and outdated version of our sample store. The new sample store is the Blue Sky Music sample. It is much more complete and up to date. If you have access to it you should definitely be using this version of the sample store.
The dynamic dropdowns section is meant more as a marketing inclusion than an example. If you are trying to create a dynamic dropdown set of select lists I would suggest starting in the help for Dynamic Dropdowns and looking at the example there. There is also a Getting Started Guide that is available for this on the support page here:
Please post any questions that you have about any of this functionality.