I loaded 3 sticks today and I had one that would not pair After several attempts I cancelled the bluetooth and went with IR
I then went through everything and went to settings ,remote and accessories and it scanned in the remote no issues
When you highlight the m3u line that you are using there should be an icon at the bottom of screen saying edit It should be blue.Whether or not the button is blue it is the bottom right button on your remote that you should use as dishuser stated.