If you know how to use playlists and Smart Playlists in Music, then you're well on your way to mastering them in Usher—they work an a near-identical manner in Usher.
In case you're not familiar with them, think of a playlist as the equivalent to a real-world photo album: Adding media files to a playlist is very similar to putting a photograph in a physical photo album. (The main difference is that your real-world photo is moved into the album; in Usher, your media file is added to the playlist, but it isn't removed from your library.)
Once you've created a playlist, its contents won't change unless you manually add (or remove) media files—just as with a real photo album. A Smart Playlist, on the other hand, is like a magical photo album: You simply tell it what you'd like to see in the album, then the album itself goes out and finds all the matching photos.
A Smart Playlist uses a set of criteria you define to find matching entries in your media library. Unlike a playlist, a Smart Playlist is dynamic: If you add a new media file that matches a Smart Playlist's criteria, that file will be automatically added to the Smart Playlist.
A regular playlist is a great place to store media files related to a non-recurring event—if you want to see all the media files related to a trip you took last year, a regular playlist will do the trick. (As you're unlikely to add more files about a trip you took in the past, you're not worried about automatically keeping this playlist current.)
A Smart Playlist could be used, as an example, to categorize all the movies you have that were directed by some named director, or that starred one or more of your favorite stars, etc. As you will probably add more such movies in the future, a Smart Playlist would always reflect your latest additions.
For full details on Smart Playlists, see the next chapter. Here's everything you need to know about regular playlists.
To quickly jump to the end of a long playlist or Smart Playlist, right-click in a blank area of Usher's main window title bar. Right-click again to jump back to the beginning.
Creating Playlists
To create a new playlist, select
→ , or just press ⌘N. You can also Control-click in any empty area of Usher's sidebar and use the contextual menu.Prior versions of Usher featured a small bar at the bottom of the side column; from the bar, it was easy to click an icon to create (or delete) either a playlist or a Smart Playlist. It may appear that feature has been removed from Usher 2. It's still there, though it's now hiding by default.
To see the hidden playlist bar, hold down the Control (⌃) key; to see the hidden Smart Playlist bar, hold down the Control (⌃) and Option (⌥) keys:

The previously-hidden bar will disappear again when you release the special keys.
Working With Playlists
To add items to a playlist, select media files in the Sources section of Usher, then drag-and-drop the selected item(s) onto the desired playlist in the sidebar. That's really all there is to it.
To remove, select one or more (Shift-click) files in the playlist, then press Delete, or Right-click and select Delete from the contextual menu.
You can copy one or more media files from one playlist to another by dragging and dropping—again, you can use Shift-click or drag a selection to select multiple files.
If you were to try this with a Smart Playlist, it wouldn't work, because Smart Playlists are defined by rules—you can't manually add or remove anything to or from a Smart Playlist.
Organizing Playlists
You can rearrange your playlists by dragging-and-dropping; you can even place one playlist inside another—and this behavior isn't restricted to playlists in playlists. As seen in the image at right, you can place a Smart Playlist inside a normal playlist—"The Movie Biz" was a new empty playlist; it turned into a folder when the "Behind the Scenes" Smart Playlist was dropped onto its icon.
This lets you create further levels of organization, and it's possible because a regular playlist is really just a folder that usually contains media files.
While both playlists and Smart Playlists can be placed inside a playlist, you can't put either type of playlist inside a Smart Playlist, because a Smart Playlist isn't really a folder of any sort.
Deleting Playlists
To delete a playlist or Smart Playlist, select it with one click, then press Delete. Alternatively, Control-click on the item to be deleted, and choose Delete Playlist (or Delete Smart Playlist) from the contextual menu.
Deleting a playlist will never delete your source media files. The only thing that will be removed is the playlist itself.