Creating Slider in wordpress theme with custom post

Perhaps in your post loop you would need to add a condition that checks for post type, using the get_post_type() function.

So something like this:

<?php if(have_posts()) : ?>
     <?php while(have_posts()) : the_post(); ?> 
           <?php if(get_post_type(get_the_ID()) === 'your custom post type') : ?>

                    //Your slider code with current post data


           <?php endif; ?>
      <?php endwhile; ?>
 <?php endif; ?>

you could obviously add extra conditions for if the post type isnt found or i have_posts doesnt return anything.