A vector has both magnitude and direction. Firstly, you need to be able to write a line segment joining 2 points in Vector form . Then you need to identify direction cosines, direction ratios, unit vector, Triangle Law.
You then move to Dot Product, Cross Product, how to calculate them and finding the projection of one vector on another vector.
As an application, you can also learn how to find the area of a triangle and parallelogram using cross product.