how can I test the square payment method?

I want to test if my webpage is HTTPS compliant.  It seems to be and yet I am told it is not.

So, I need to test the payment method.  I know there is a sandbox method, but I am not able to access it

In the integration settings there is a "Mode" option.  Change this to "Test Mode" to test payments.

Test card numbers can be found in the following page:

https://docs.connect.squareup.com/articles/using-sandbox