To put this on your homepage, go to:
Appearance > Editor
then on your right look for the homepage file, usually home.php. Click on it.
At the top it should/might say:
<?php get_header(); ?>
Under this, paste:
<?php if ( function_exists( 'get_wp_parallax_content_slider' ) ) { get_wp_parallax_content_slider(); } ?>
Scroll down and click Update File to save it. Make sure you’ve activated the plugin and selected a post category, then have another look at your homepage, it should be there.