I have numerous playlists synced between my iPhone 8 and my Apple watch 3. When I first brought up the music app on the watch, it showed me all of my music playlists. I selected one and began playing it through my paired bluetooth headphones (Bose QC35). I can see the various songs on that list when I scroll down, but I cannot now find a way to get back to the main screen where I can select another list. How is that done? Thanks.