Tracks can be downloaded by clicking on the "FREE" button on the right hand side of the track and also streamed directly from this website.  You can navigate to the specific second of the track that you are listening to by clicking on the gray bar above the list of tracks.
Tracks 3-7 and 19-28 are general technique excercises. They are relevant to the learning of Clan Campbell's gathering but as they concern pieces of execution found in piobareachd generally they will be useful for the study of other tunes as well.