window.dataLayer = window.dataLayer || [];
window.dataLayer.push({
'event': 'checkout',
  'ecommerce': {
    'currencyCode': 'GBP',
    'checkout': {
    'actionField': {'step': '1'}, //there is only 1 step, so it is just ‘1’
           },
      'products': [{                            // adjust product array according to the order data
        'name': 'Stress-Ball Paul',
        'id': 'SK DEADPAUL1',
        'price': '7.50',
        'brand': '', //if brand is not applicable, just use empty string
        'category': '',
        'quantity': 1
       },
       {
        'name': 'Cable Holder',
        'id': 'GW CABLEHOLDER1',
        'price': '5.00',
        'brand': '', //if brand is not applicable, just use empty string
        'category': '',
        'quantity': 1
       }]

   }
 });