I need to understand what api calls to make to authenticate with clover. I am assuming OAuth is the protocol. What is the login process workflow? What api calls need to be made to make this happen? What does the client have to enter to authenticate with clover. I understand they need a merchant id. I would like that saved in a config file so they don't have to always re-enter it. I have a simple login page which is only password and want to keep it that way.