It is frequently helpful, in order to create a fully-functional website, to be able to store, manipulate, and display lists of objects.
Thankfully, there are a number of liquid tags and filters that exist solely for that purpose - in addition to the methods to fetch lists from sites. Some of the most helpful are:
Following those links should provide several helpful examples of how these can be used to easily fetch information from the site, manipulate it, and display it however you want.