Can you explain me the process or steps to integrate shopify channel like shiprocket or nimbuspost?

I want to build the channel integration of shopify in the project Like shiprocket, nimbuspost does in there site where user enter there api details and then I ship the orders by selecting a courier company which i integrate. I just want to know the process or steps to be done so that i can do it which the company like shiprocket or nimbus follows to integrate channel in there Site ?