How can I tell how much oil to add when the oil light comes on and goes off?

I do not see a dip stick, where is it located?

Well I'll be dipped!.. It ain't got one, my bad... See owners manual or... Here is a link to a YouTube vid that shows how to check oil level but.. I guess if it's low, just add oil until the onboard system says it full...... Very poorly designed.... Now that's really technology at work.... Got rid of that archaic and expensive dipstick to save some money! ... (BMW)