Generally to define the processes for QMS, You should have to form a team and process owner should be part of the same . Process owner has to give the process steps in lay man lauguage and other team members should have to add the input in it . Generally for QMS the rule to prepare proess is "write what you do and follow what you have return "
after that you have to update and improve it by using quality tools
It is very simple method what i learned as per my experience
Thanks .