Add cues

Add the Jingle1.mp4 media on cue 3.

Set the Media mode to Last frame so the media will only play once.

Add a fade in of 2 seconds.

Now add the Jingle1_Loop.mp4 on cue 4 in loop mode and with a fade in of 2 seconds.

We will set this cue to be read automatically after cue 3 is finished reading.

You could do so by setting a Wait command on cue 4 of the same length as the media on cue 3, but this would not automatically update if the media on cue 3 is changed.
It is better practice to use the Follow command on cue 4 which will automatically launch the cue, taking into account fade times, when the previous cue is nearly finished reading.