This is often a tricky area, however, it is just using GCSE maths in new situations.
Scalars vs. Vectors
It is essential that you can distinguish between vector and scalar quantities as well as recalling many examples of each. Remember a vector has magnitude and direction!
Displacement vs. Distance
Although similar, displacement and distance are quite different and you should understand the difference between the two, as well as realise the importance of which term you should use when.
Adding Vectors - Graphically and Mathematically
If you wanted to resolve the forces on an object, or find the resultant velocity, then you have to be able to add vectors together. Most of the time the two vectors you combine are at 90 degrees and you must be able to use trigonometry or scale drawing to find the result.
If several forces act on an object then we can add or subtract these vectors to work out the resultant. This can be mathematically or through scale drawings.
If you have a vector acting an an angle it is often useful to consider its components in the x and y direction. By remembering SOHCAHTOA and applying it carefully you can resolve the vector into its separate components.