Hi Trevor,
It's very simple once you get the hang of it.
There are three different actions available, and each action depends on whereabouts in the highlighted bar you click.
If you click on the three dots on the right hand side (...) you will be presented with 'Delete', 'Add to Playlist' and 'Rename'. I call this 'Edit mode'
If you click anywhere in the centre of the highlighted bar, then that artist or album or track will be opened up in the right hand windows, but nothing will be played. This is what I call 'Browse mode'
Then if you click on the arrow on the left side of the highlighted bar then that artist, album or track will play, This is 'Play mode'.
Then once you have got your selected music playing, you can go back into 'Browse mode and view other artists, albums or tracks and this is not interfere with the music that is currently being played. Until you go into 'Play mode' by clicking on the left side of the highlighted bar again.
Regards,
Peter.