Add below code in child theme functions.php file or WP Admin - Plugins - Editor - WPLMS Customizer - wplms_customizer.php
Refer WP tutorial : https://codex.wordpress.org/Plugin_API/Action_Reference/admin_init
function restrict_admin_with_redirect() {
if ( ! current_user_can( 'manage_options' ) && ( ! defined( 'DOING_AJAX' ) || ! DOING_AJAX ) && $_GET['type'] !='upload' ) {
wp_redirect( site_url() );
die();
}
}
add_action( 'admin_init', 'restrict_admin_with_redirect', 1 );