Good Evening Roybert:
There is no such thing as a stupid question.
To the best of my knowledge minimum requirement is a ATPL multi-engine Class 1 instrument rating which takes about 1500 hours (if I am wrong anyone please correct).
In the "old" days entry level was S/O on either DC-8 or B-727 with the very odd lucky person as F/O on the DC-9.
As this is a seniority driven position you bid on what you think you can hold and if no one bids the position and it is open that position will go to the new hire pilot. Each course of new hires the company will determine what positions will be filled say they have a need for B-787 relief pilots all of the course could go as B-787 relief pilots.
Anyone with more current updated information please add to this posting.