1. Check the back of your art . There should be metal sawtooth cleats for hanging. Most of the time they are placed at the center or either end of the frame. Another hanging system is simply to use a wire. The wire is attached to the picture frame usually a few inches from the top and with a small eye screw.
2. Choose the right size and type if nail to hang your art pieces. If a wire is used for hanging then use a picture hook otherwise, a nail should do the trick. For those of you who might not know, a picture hook is a small metal piece with an angled arm that allows the wire to sit into the angle. A nail is used to anchor the hook to the wall.
3. Now lets talk about proper height placement.The general rule of thumb is to hang at eye level as I mentioned. The center point of the painting should be at eye level. Since we are all at different heights then the bottom of the frame should be about 12 to 18 inches above the back of the furniture. If you're hanging on an open wall, then the bottom of the art should be about 60 inches from the floor. But remember there is always room for a few inches either way. Take into consideration the scale of your furniture and the relationship it has to the art piece. Use your eye and judgement to determine the correct height and you'll be fine.