We're in the process of updating the documentation for Zotero 5.0. Some documentation may be outdated in the meantime. Thanks for your understanding.
Items in the center column can be sorted by various properties, such as their title, creators, or the date they were added to your library. For a quick overview, watch the sorting screencast.
To change the way items are sorted, click on any of the headers at the top of the center column. For example, if you click on “Title”, all your items will be sorted alphabetically by title. Clicking a header multiple times toggles between ascending and descending sorts (the header will show an upward and downward arrow, respectively).
You can change which properties are shown in the center column by clicking the sort icon (), found to the right of the column headers. Checking properties in the dropdown menu adds them to the center column, and unchecking removes them.
By default, properties in the center column are arranged from left to right in the order in which they are shown in the dropdown menu. You can rearrange them by dragging and dropping the headers. To reset the order, select “Restore Column Order” in the dropdown menu.