Hi,
took me a while as well.
Thorough clean up of all surface rust, then degreased.
Two tins of etch primer (light dusting), dried overnight, then a good coat of zinc primer - if using this I would definately ensure you have good ventilation. Not with just the garage door open - might start seeing things!!
Left that to dry for awhile, had to work and then 1 coat of chassis black. It does need a bit more black as there as been scratches along the way but looks ok.