Someone asked about joining cargo etc. You will need an approval letter from QR Human Resources that you need to present to QR Cargo at your port of departure (can be scanned and emailed). They will guide you on packing etc. I guess you can do it when you depart for Doha but it can be done anytime after you've been accepted for employment. Your joining coordinator will help you.
Once you are here, it is organized chaos, lots of paperwork, but it all gets done in the end.