The Moen Annabelle faucet has a single handle fitted to the side of the base. This lever style handle is orientated vertically and pulls to the side to begin the flow of water. This action often results in a dropping handle, which requires adjustment from time to time. Even if you have no experience fixing things, this task is a breeze. All you'll need are a few tools and about a half hour.
Shut off the water to the faucet. Close both the valves on the two pipes under the sink by rotating them clockwise.
Find the small round plug on the bottom of the faucet handle lever and take it out. Pry it out with a small screwdriver or pair of pliers. Slide an Allen wrench into the hole where the plug was. Turn the set screw in this hole counterclockwise and take out the screw.
Slide the handle off the faucet. Turn the dome cap -- the dome shaped part under the handle -- counterclockwise and pull it off.
Realign the curved shaped piece fitting over the cartridge stem, the square shaped rod sticking out of the faucet base and the part the handle slides onto, so it accepts the handle, if necessary. Position the two round washers to allow the part to fit properly on the stem, if necessary.
Place the dome cap back on. Slide the handle back over the stem and push it flush against the dome cap. Insert and tighten the screw to secure the handle in place on the stem.