SAB- setting to avoid suggest a video

I am wondering if anyone can help me with this problem I am having. After someone watches a video embedded into my SAB app, youtube will suggest another video. I want to turn off video suggestions. I have heard you can do so as follows:
But that did not work for me.

Try putting ?rel=0 at the end of your video’s URL directly at the end:

Hello @craig,

I suggest you follow the below steps.

  1. Go to Video tab and add your videos there.
  2. Go to Video Settings and check the last option (after playing a Youtube video, related videos should come from the same channel as the video that was just played.)