if you want to transfer money at the ATM, you must first go to the counter of China Merchants Bank to open the ATM self-service transfer service, otherwise you can't directly repay the money at the ATM.
According to your requirements, the most reasonable way is to call the customer service to help you draw the money, and the amount can be determined by yourself. However, if you haven't done similar operations before, the customer service will give you a prompt for the first telephone repayment, and you can just follow the prompt, and then make a call for each repayment.