how add shipping charge in amount

[thehiddennepali]

Hi I am just figuring out how to include the shipping charge for the amount as i have line of item and i have fixed delivery charge but need to be from database to the paypal
{ currency_code: 'USD', value: (<?=$total;?> + <?=$delivery_charge;?>).toFixed(2), breakdown: { item_total: { currency_code: 'USD', value: <?=$total;?> }, shipping: { currency_code: 'USD', value: <?=$delivery_charge;?> } } },

i want to use configuration some think like about but i can't figure out how to overwrite the amount

can you please let me know how i can do that or provide any reference or guide