I haven't had to do this, but if it were me:

I would have a second hand to operate the jack cause I would be holding the door out at a 90* angle.

Put a block of wood on the jack to prevent damage to the bottom of the door.

 

I still have the running boards that mine came with (is that what you call them). I placed the jack on them and cranked it up. I watched to make sure I only lifted the door about half way then lowered it sprayed it and pulled them off. I did put a rolled up towel on the jack to prevent damage directly to the door.

I would guess if you have some cinder blocks or some wood to put your jack on it would be much easier.

I rolled up towel on the bottom of the door helps also when trying to pull the doors off if they are stuck, really saves your hand.