tah, if your playlist is in the right hand panel of the app, you need to move it to the left hand panel. Select one track on the right, stick a finger on it until it’s highlighted. Then go to the bottom of the screen, select the icon with the ’check mark’ in it, that will highlight all your songs. then go to the bottom of the app screen again, the left icon with load your selection on top of everything previously in the lefthand panel, another loads your selection at the bottom of the lefthand panel, yet another will load your selection to the lefthand panel and erase anything else that was previously there. Play with it some. This is how my T2 works, hope your device is similar.
Hold your finger on a song for a moment, deleting it will be an option. I think in the right panel, might be both.