Once you have organized your media files to create your library, the first step in using the library is to add the top-level folder(s) on the Library tab in TealPlay Settings. You can access the Settings window by going to Tools...Settings. Navigate to the Library tab, then use the Add button to locate and add one or more folders.
After the library has been scanned, the library tree will be populated in the lower left corner of the main TealPlay window:

To navigate the library, click the small arrow symbol next to any container element to expand that container and show its contents. If navigating with the keyboard, use the up and down arrow keys to move within the library. Expand containers using the right arrow key, and close containers with the left arrow key.
As you select items in the library, information about each item will appear in the display box to the right of the library tree. The type and amount of information will vary based upon the available metadata for the library item that is currently selected.
TealPlay always plays files from its playlist, which is located in the upper right corner of the main TealPlay window. In order to play media from the library, it is necessary to add the media to the playlist. There are several ways to accomplish this task:
You can select multiple library items by holding down the CTRL key (CMD key on a Mac) and drag them all to the playlist together. If you drag a container item to the playlist, it will be replaced by all the playable items that are descendants of that container. By default, TealPlay will begin playing the first item added to the playlist automatically. This behavior can be changed in Settings.
It is possible to add content from the library to the playlist randomly. This functionality is useful to created mixed playlists that contain shuffled files. To add random content, go to Tools...Randomly Add to Playlist in the menu to display the random items dialog:

This dialog displays the library tree with checkboxes next to each item. Checking or unchecking a container item checks or unchecks everything inside that container. Note that only playable items are selected for addition to the playlist, so it is the set of checked playable items that is used to pick random ones. If a container is checked but all of its playables are unchecked, then no items from that container will be picked.
Once the scope of possible random items has been decided, the number of items to add to the playlist is set in the box below the tree display. Multiple random items can be added in the same operation.
For performance reasons, TealPlay maintains a cache of library information. If any changes are made to the library folders, including reorganization or adding/removing media or metdata files, then it is necessary to rescan the library. Rescanning is accomplished by going to File...Rescan Library or by pressing CTRL+R. If the library folders are changed in Settings, a rescan is triggered automatically. Rescanning the library may take some time, especially if the library is stored on mechanical disks or other slow storage. Progress information will be displayed in the library tree area as the scan progresses.