Similar (like) magnetic poles repel. Unlike magnetic poles attract. A magnet attracts a piece of iron. The most important of the two properties of attraction and repulsion is repulsion. The only way to tell if an object is magnetised is to see if it repels another magnetised object.
The strength and direction of a magnetic field is represented by magnetic field lines. Field lines by convention go from North to South. A magnetic field is three-dimensional, although this is not often seen on a drawing of magnetic field lines.