Music MiniPlayer lets you change your music source/playlist as long as it’s a local or Apple Music playlist that resides in your Music Library. To get started, click the Toggle Drawer button in the LCD display. It's a circle with triangle shape within it.
Upon clicking the button, it will open a drawer below Music MiniPlayer. You will see a popup button which displays a list of your available playlists in Apple Music. Select a playlist and click the 'Play' button to begin playing it.
This drawer also contains the Shuffle on/off as well as the Repeat All, Repeat One, or Repeat None controls.
Click the Toggle Drawer button once more to close the drawer.