Not saying this is the right way
but i haven't been crushed yet
stick the jack under the k frame
if you don't care about the frame paint make sure one of the lips on the cup extends into the very edge of the sump U shape in the frame so if the jack doesn't move on its wheels the cup doesn't slip too far across the base of the K frame.
if you do care about the paint on the frame use a nice rubber insert like th tyre places use in the cup. Or a circle of flat plywood that's taller than the cup kinda works
the bigger the jack
the bigger the cup
the less damage you cause becasue the weight is spread across the K frame bottom rather than concentrated in 1 place
Jack it to the max
stick the stands under the chassis rails a few inches back from where they kick up to the front suspension mounts (by the torque boxes on Aussie/cabrio/hemi cars)
i.e you want the stands where they can't slip.
the front of the car will droop a small amount when you remove the jack, some of it is the car rising slightly at the rear suspension and some of it is genuine bending of the car!!!!...... but that is normal (thats why there is a slip joint in the steering coupling!!!!)
provided you are on smooth ground and the jack has nice wheels you could then, if you so wanted, jack up the rear and use stands under the axle tubes or rear sub frame near the spring mounts in front of the wheels .
Only necessary if you are painting or waxoyling. most other things you are working at one end or the other
but i tend not to jack both ends, as i like at least 2 wheels on the ground and if i'm under the front i like the hand brake on....
if its a manual take it out of gear before testing starter
dave