How to change the sequence of the playlists

With all your playlists listed before you in Playlists page, tap the "pencil" icon in the top right corner. Then the order menu will appear in the left of each playlist. You can arrange the sequence of your playlists by draging the menu up or down, and then tap the "tick" icon to confirm.

When you enter a playlist, tap the sort icon. You can choose Sort by time added, Sort by song name, Sort manually, Sort by number of times played (The sorting method of different app versions is slightly different).