Referring to Slide Array

Hello,

I’m still trying to create bullet indicators but I might need help.
I did some research and from what I understand, I could create indicators somehow like this?

add_action ('__before_carousel_inner', 'bullet_slider_select');
function bullet_slider_select() {
   		$slides = (); // its array maybe?
   		$countslider = 0; //counter 
   		echo '<ol class="carousel-indicators carousel-nav">';
   		 foreach ($slides as $item){
   				echo '<li data-target="#myCarousel" data-slide-to="'.  $countslider++ . '"> </li>';
   			}
   		echo '</ol>';
   		
	}

If this is incorrect, any input or suggestions would be appreciated as I’m a newbie with PHP.
Thank you!