Meta Box

I sent a message via the contact form a few days ago. Did you receive it?

Hi again - can you please respond to my last message?

Thank you for the links.

I feel competent with html and css - not at all with php. Will php be necessary to be able to use the full functionality of Meta Box even when/if Meta Box integrates with Oxygen?

Can you tell please me where I would input the following (snippet code or code block)?
(It's a cloneable group)

$group_value = rwmb_meta( 'group_id' );

array(
    'sub_field_1_key' => 'sub_field_1_value',
    'sub_field_2_key' => 'sub_field_2_value',
    'sub_field_3_key' => 'sub_field_3_value',
    //...
)

$value = isset( $group_value[$sub_field_key] ) ? $group_value[$sub_field_key] : '';
echo $value; // Display sub-field value

array(
    array(
        'sub_field_1_key' => 'sub_field_1_value',
        'sub_field_2_key' => 'sub_field_2_value',
        'sub_field_3_key' => 'sub_field_3_value',
        //...
    ),
    array(
        'sub_field_1_key' => 'sub_field_1_value',
        'sub_field_2_key' => 'sub_field_2_value',
        'sub_field_3_key' => 'sub_field_3_value',
        //...
    ),
    //...
)

$group_values = rwmb_meta( 'group_id' );
if ( ! empty( $group_values ) ) {
    foreach ( $group_values as $group_value ) {
        $value = isset( $group_value[$sub_field_key] ) ? $group_value[$sub_field_key] : '';
        echo $value; // Display sub-field value
    }
}

Thank you for your reply.

I am getting the return of 'function does not exist'.

I have this code snippet created: https://moveyourfamilyabroad.com/wp-content/uploads/2021/05/Screenshot-2021-05-02-104348.png

I used the PHP Function Return Value. I am unclear what is entered in the argument line. I've tried entering various values with all the same result: https://moveyourfamilyabroad.com/wp-content/uploads/2021/05/Screenshot-2021-05-02-104431.png

Can you tell me please if I'm entering the wrong info into the Php return value option or where else I may be going wrong? Thanks!