What steps to take when talking out a problem between two people?

you need to act as a mediator

let the first person go with his version of the problem, while the rest of you listen

let the second person answer the first persons questions if need be and then give his/her version of the problem

As a mediator you need to determine where the misunderstanding and miscommunication arose

As a mediator you need to offer your views and ensure an amicable resolution