Vectors can seem complicated at first but they are simple once you understand that you need two pieces of information in order to define a vector. A vector is composed of direction and magnitude. You can think of them as arrows, so the direction is where the arrow is pointing and the magnitude is how long that arrow is. examples: a) ---> b) <-- So a and b are two vectors where the first one is pointing to the right and has a magnitude of three (it is formed of three small lines) and the vector b is pointing to the left and has a magnitude of two. So with the use of arrows we can define any vector, in 2D and 3D. Now vectors are more used than you expect, there are many vectorial values used in physics such as movement or displacement, eg. to describe where you have moved, direction and distance, or velocity, where you are running and at what speed.