After oil change level not showing on dipstick?

I have a 2002 Mercury Villager that depicts in manual that it takes 4.2 quarts of oil. After oil change I added 4 quarts, checked dipstick without starting and nothing shows on stick and it's completely seated back in tube. I am afraid to start without seeing oil on stick, am I suppose to turn engine over to get a reading?. I pulled the drain plug to see if oil went into pan, and yes it flows out strong, re-added what I took out and still no reading - am I safe to turn over engine even though stick has no reading, completely dry??????