Add code to autoplay slideshow

This is the code on my homepage that creates my slideshow…

<section class="homepage-slider flexslider" id="gallery">
			<ul class="slides">
			<?php foreach ($attachments as $key => $image) {
				echo "
<li>".wp_get_attachment_image( $image->ID, 'page-gallery' )."</li>
";
			}  ?>

		</section>

I really need help with learning how to add the correct coding to all this slideshow to auto play. In reading about code the best I could find was that I need to set animation = true, but as I am not great with coding, please help me and show me how to write this into my existing code structure or if this is wrong help show me where and what coding I need to add to allow the slideshow to play on it’s own and it would also be helpful if I could set the speed. Thank you so much!