Adding a Square Payment Portal to version 8.5.1

Been away from developing sites since I last updated to 8.51. I need to add a payment/checkout method to one of my personal sites and would like to use Square if possible since they are already my payment processor. Spent 2 hours on a chat with them, and got nowhere other than to build a site on their platform. Is there a method for adding Square? Thanks in advance.

@mesuva is the man to talk to