How can I let a home slider to play automatically not only manually? This is an example of a slider that I used but there is no example of both playing (manually and automatically) :

Slider demo

What should I add to the JS code? Any help?

Seems the linked example can be run either manually or automatically. Do you want both?

Yes, I am asking about running the slider both, manually and automatically.

I don't think it's easily done, for example you may need to disable the automatic slideshow when the user clicks the controls or hovers over the images.

Try find another one that does both things out of the box.