Order custom fields

[ghost]

Hello,

how can I add custom order fields.
In the docs I found this example:
<script id="snipcart" data-api-key="{YOUR_API_KEY}" data-cart-custom1-name="Comments" data-cart-custom2-name="Rating on 10" data-cart-custom2-options="1|2|3|4|5|6|7|8|9|10" data-cart-custom3-name="Do you accept terms?" data-cart-custom3-options="true|false" data-cart-custom3-required="true" src="https://cdn.snipcart.com/scripts/snipcart.js" type="text/javascript"> </script>

But it doesn't add the new fields. Just a new empty tab (that it skips).

thank you