Add a childthem to the courcepress theme

I'm using the courcepress theme, but would lik to do some chanbges, how can i create a childtheme to it when it is wthin the plugin folder.
Should the child theme be wthin the subfolder of the theme foler or the /plugins/coursepress/themes/foder ?
also how should the
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/css/responsive-nav.css' );

Look?