Trying to Understand Shortcodes.

I would recommend using a shortcode, because its easy to use and at the same time efficient.
Below I have attached the code, how you can put your code into a shortcode.
the add_shortcode function is what you use when you want to create a shortcode.

To use it, you simply need to write [render_slider_shortcode] anywhere you want your slider to be displayed.

PS: There might be some error in the code which you gave. I coudnt test it on my site. But rest is fine. If you come accross any errors, make sure your code is getting proper values.

    // display a sub field value
add_shortcode('render_slider_shortcode', 'renderSLider');
function renderSLider()
{
  if ( is_page("Home") ) {
    if( have_rows('slider') ):  ?>
      <div class="my-slider"><ul >
      <?php
    // loop through the rows of data
      while ( have_rows('slider') ) : the_row();

  $image=get_sub_field('image');
   $title= get_sub_field('title');
   $byline= get_sub_field('byline');
  $link=  get_sub_field('link');


  ?>
  <li>
  <div style="background-image: url(<?php echo $image; ?>); min-height: 600px; background-repeat: no-repeat; background-size: cover">

    <h2><?php echo $title; ?></h2>
    </h3><?php echo $byline; ?><h3>
    <a href="https://wordpress.stackexchange.com/questions/217378/<?php echo $link ?>"></a>

  </li>


   <?php endwhile ?>
    </div>
    <?php 
    else :
    // no rows found ?> 
       <?php 
      endif;
      }   else {
    // This is not the blog posts index

    }
  ?>
  </li>
 </div>
  <?php

}