If you need to manually open the gate the first thing you'll want to do is grab your owner's manual. It's always best to have a formal training by your gate opener repair company. Many gate operators come with a manual release key that when inserted and turned the gate will be able to be moved by hand. If you have a slide gate operator the fastest option is removing the nut on the chain adjusting bolt that attaches to the chain. This will make it so you can move the gate by hand. Some swing driveway gate openers have red lever handles and simply lifting the lever will loosen the hub enough to make it so you can move the gate by hand.