Blink next button of storyline player when the timeline end of the slide.

Hi, Peter, and welcome to E-Learning Heroes! ✨

I looked at the .story file Saurav shared, and here's what I see happening:

• The red rectangle is not connected to the blue line. The blue line is an image with a wipe animation applied to it. If you click the animation option on the ribbon, you will see little stars indicating which objects have animations:

• The red rectangle has an entrance animation and an exit animation. The triggers create a loop (the entrance animation makes it disappear, and the exit one makes it re-appear). The triggers also connect to the Next button, so the blinking happens by making the button disabled and then enabled. 
• The signature is on the Slide Master:

I hope this helps!