You can view your collection of items in many ways. At the top of the middle panel, different fields are listed: Title, Creator, Date, etc. You can click on any of these fields to view them in a different order: Title A-Z, Title Z-A, Date Newest to Oldest, Date Oldest to Newest, etc. With the icon on the top right, you can select other fields with which to view your items. For example, below, "Date Added" was selected.
At the top left of your Zotero program is a folder button with a green plus sign. Click this to create a new "collection."
Create collections to organize your references. Collections are like file folders on your computer, but a reference can be in more than one collection at a time. In other words, a book on the Civil War could be filed in your "Civil War" collection, your "Georgia History" collection and your "19th Century America" collection without having to make three copies of the reference.