There are two types of can openers. One is electric and one is a manual opener. The manual method is not for everyone, but it does work very well (and if you're trying to go green and save money, you might find the manual method the way to go). The electric method is the preferred method because there is very little physical labor involved. Learn how to use a can opener manually and electrically.
Plug the electric can opener into an outlet.
Lift up the silver lever that raises the cutting wheel into the air. Place the lip of the can under the wheel. Then bring the lever down and press hard enough to make the wheel insert into the can.
Press the On button while holding the bottom of the can and it will automatically turn as the wheel slices through the can lid.
Remove the can from the opener when it reaches the end and you feel a slight drop of the can. The lid will remain attached to the magnet on the opener and the can is ready to dump.
Take the manual opener and spread the two handles apart.
Place the wheel on the lip of the can and squeeze the two handles together, which will bite into the can lid by the lip.
Turn the butterfly lever on the opener in a clockwise direction. If you feel a miss in the can lid, turn the lever counterclockwise to redo. Then continue moving forward by turning clockwise.
Continue turning the opener until you come to the end where you first started the cut. Remove the opener and use a fork or a butter knife to raise the lid and remove it.