Click the Zotero button at the bottom of your browser to open your library. At the top left 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, an article on swine flu could be filed in your "Swine Flu" collection, your "Public Health" collection and your "Epidemiology" collection without having to make three copies of the reference. To add a reference to a collection, just select an item in the middle column, and drag and drop in the collection folder in the left column.
In addition, once you have created a collection you can easily move it, by dragging and dropping, to create a sub-collection within an existing collection.
You can use or delete tags already associated with items in your library, and/or you can create your own unique tags to keep track of your items.
Select an item in the center column of your library, then click on the "Tags" tab in the right hand column. Tags already assigned to an item will be listed with the yellow icon labeled "Automatically added tag". To add a tag, click on the "Add" button, and a text box will appear at the bottom of the list of tags. Once you create a tag, it will appear alphabetically in the right hand column associated with the selected item with a blue icon labeled "User-added tag". All of your tags will be listed alphabetically below your Library in the left hand column.
You can link related items in your Library, even if they are not in the same collection.
Select an item in the center column of your library, then click the "Related" tab in the right hand column. Click the "Add" button, and you will get a drop down menu asking you to "Select Items" from your library to link or relate to your original item. Items linked in this fashion will be listed in the "Related" field of the other item.