Hello,
I can’t tell from the documentation. I want to use Square Payment APIs only (as in without Web Payment SDK) to send the payment (Call CreatePayment) to the Square-hosted checkout page (call CheckoutPaymentLink), but it looks like SDK is required.
I am completely new to building apps and using APIs, so some guidance in this area would be great.
Thank you.
If your going to use the Payments API you’ll have to use the Web Payments SDK. That’s the only way to generate the source_id that’s passed to the CreatePayment request. If your going to use the payment links from CreatePaymentLink you won’t call CreatePayment. The generated link will take the customer to the Square hosted page where the payment will be processed. 
Ah.
See, I got the two different methods mixed up. Thank you for clarifying. I will need to try this out.
I now would like to confirm something. Square Docs says the CreatePaymentLink specifies the order. Am I correct to take that as meaning I do not have to call CreateOrder?