@Dominicana: When you are playing a track on Samsung Music, look at the foot of the screen where the controls are located and check the far right option. If your tracks are currently repeating over and over then it probably has the letter A surrounded by arrows. Please tap this symbol until it changes to the letter A with a straight arrow below it, and this will play your tracks in order without repeating. Hope this helps.
No problem, @Dominicana. There's no Stop button, therefore you can either hit 'Pause' or swipe from the top of the screen to the bottom and close Samsung Music in the notification panel by tapping the 'X' in the top right.