Sliding pictures in modal window

Hello again!

I tried to slide (animate like in slider) prev and next images in modal window. I tried to adopt code from this codepen but it don't working for modal window's clicked images.

Code like also not working.

$('.btnModal-right').click(function(){

    imageClicked.next().find('img').trigger('click').animate(...);
	
});

Can't find the tutorial. Seems like all coders know combine well-known plugins. But i want to make it by hand for to understand algoritm. If some one knows the good tuts about it or have the idea how to do it, please let me know!

Thank you!