How to Insert Shortcodes into Theme?

You can hardcode shortcodes into a theme using do_shortcode.
http://codex.wordpress.org/Function_Reference/do_shortcode

echo do_shortcode('[wp-like-locker] Your locked content here... [/wp-like-locker]');

You will most likely want to replace the hard-coded “Your locked content here…” with the function that pulls the content from the editor, like the_content
http://codex.wordpress.org/Function_Reference/the_content

It might look like

  // the loop
  $content = get_the_content();
  echo do_shortcode('[wp-like-locker]' . $content .  '[/wp-like-locker]');