my oil fired furnace wont go on?

I went to check out my furnace today,we live in Vermont and the fan turns on, but the fire wont,I pushed the reset button on the motor and nothing,then I pushed the red button on top,because it was out of oil,got some and now i hear it kida hissing.so I thought maybe air was in the line,but nothing turns on to even get he air out..Help!!!