1992 Ford Tempo WHERE IS THE OIL PAN?

The oil pan is right under the engine also known as the crankcase-oil light On-if there's no knocking noises could be the oil pressure switch out of calibration

You didn't say why you need to find oil pan? If the oil light is on, you need to check oil level in pan by looking at the dipstick. You do this with engine NOT running. Open hood and look for dipstick. Pull it out and wipe it off. Pit it back in and pull it out again and read oil level. If you need to add oil, do so thru screw off cap usually on engine valve cover. Do not overfill.

If you really are asking where dipstick is to check oil look in your manual. If you dont have manual get help from someone who knows about cars locally. Dont drive or run engine till you get this resolved as it may ruin motor!