You can think of metals as large structures of metal atoms held together by metallic bonds. Often metal bonding is described as a sea (like ocean) of free moving electrons around the positive metal cations. Because the delocalized electrons can move, they exhibit properties such as conducting electricity or being able to be bent or stretched. Video by Bozeman.
Metallic bonds can exist between different types of metal atoms as well. When this happens the are called alloys. For example Cu and Zn combine to form brass, an alloy.