Answer:
Vector quantities are quantities that have both magnitude and direction. An easily understood example is velocity, which has both speed (the magnitude component) and direction. If we say 60 miles per hour or 8 knots per hour, and we add direction, like east or west, or course 220 magnetic, for example, we're talking about a vector. Electromagnetic fields also have amplitude (a measure of magnitude) like 10 volts/m and direction east or north for example. It really is that simple, and the investigator only has to remember the direction component and add it to a magnitude to lock in the idea.
Light is not a vector quantity, it has size and the speed of light 300 mega meters/second, but it does not have a direction. Another example is like saying I was driving home at 60 mph. The '60 mph' is a speed, but not a velocity (a vector) because there is no direction specified.
It is important in science to distinguish between vectors and real quantities. Real quantities do not have a direction. This can be seen as no direction or it can be seen as omnidirectional. Omnidirectional would be wrong, at best reals could be said to be origin directional. Positive real could be said to be toward the origin and negative real could be said to be away from the origin. Vectors are related to the origin and directional axis. Real numbers define the origin and a real axis, vector quantities define specifically directions and directional axis based on the real zero point.