How to show map?

I am using following code to show map on contact page.But it is not showing up.How can I resolve this problem?

array(
				'id'   => "{$prefix}address",
				'name' => __( 'Address', 'your-prefix' ),
				'type' => 'text',
				'std'  => __( 'Hanoi, Vietnam', 'your-prefix' ),
			),
			array(
				'id'            => "{$prefix}map",
				'name'          => __( 'Location', 'your-prefix' ),
				'type'          => 'map',
				// Default location: 'latitude,longitude[,zoom]' (zoom is optional)
				'std'           => '-6.233406,-35.049906,15',
				// Name of text field where address is entered. Can be list of text fields, separated by commas (for ex. city, state)
				'address_field' => 'address',
			)
I have placed following code:
			   <div class="contact-area">
           <?php echo rwmb_meta( 'pb_map'); ?>
           <?php get_post_meta( get_the_ID(), 'pb_map' ); ?>
          </div>

https://www.ads-software.com/plugins/meta-box/