How do I prime my gas furnace, it ran out of oil

It is a oil furnace if it uses oil. There is a fitting usually on the top or side of the pump. You open the fitting a little and push the reset button. When the unit fires close the valve. This is a simple explanation and have some old rags handy to catch any oil that comes out of the valve.

Most professional service people have a set up with a vinyl hose that goes into a container to prevent the oil spill.

If you do not know how to do this correctly call the oil company that delivered the oil.