How to Hide Easy School Registration Admin Menus

function plt_hide_easy_school_registration_menus() {
	//Hide "School".
	remove_menu_page('esr_admin');
	//Hide "School → School".
	remove_submenu_page('esr_admin', 'esr_admin');
	//Hide "School → Teachers".
	remove_submenu_page('esr_admin', 'esr_admin_teachers');
	//Hide "School → Waves".
	remove_submenu_page('esr_admin', 'esr_admin_waves');
	//Hide "School → Courses".
	remove_submenu_page('esr_admin', 'esr_admin_courses');
	//Hide "School → Registration".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_registrations');
	//Hide "School → Course in numbers".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_course_in_numbers');
	//Hide "School → Add over limit".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_add_over_limit');
	//Hide "School → Payments".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_payments');
	//Hide "School → Payment emails".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_payment_emails');
	//Hide "School → Settings".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_settings');
	//Hide "School → Students".
	remove_submenu_page('esr_admin', 'esr_admin_sub_page_students');

	//Hide "Student info".
	remove_menu_page('esr_user_info_course_list');
	//Hide "Student info → Student info".
	remove_submenu_page('esr_user_info_course_list', 'esr_user_info_course_list');
	//Hide "Student info → Payments".
	remove_submenu_page('esr_user_info_course_list', 'esr_user_info_payments');
}

add_action('admin_menu', 'plt_hide_easy_school_registration_menus', 12);
Where do I put this code?