You can add tracks in the Cue window the usual way, either by double-clicking on the free space in the canvas or by choosing the Track > Add Track, Bus, or VCA menu item. The important part is to enable the Show on Cue Page checkbox in the newly opened dialog.
Alternatively, you can drop an existing audio or MIDI file into the empty part of the canvas to automatically create the cue track and fill the first empty trigger slot with it.
Trigger slots not only work as a drag-and-drop target, they also work as a drag-and-drop sources. You can drag the contents of an existing trigger slot into the empty part of the canvas to create a new track and fill the first slot with the contents of the original slot. You can also drag and drop the contents of one slot into another in case you want to use the same clip with some variations (e.g. a custom follow length).
There are several ways to load a clip into a trigger slot:
Note that the type of data must match the type of tracks when you drag and drop a file, a clip, or a region. E.g. you cannot place a MIDI clip into a trigger slots of an audio track.
The contents of this options box partially depends on the type of data in the clip, audio or MIDI. The common settings are:
The only audio-specific setting is Gain (dB) which adjusts the output volume of a clip.
For MIDI clips, there are several specific options: