Wonderful! Moving to the right means velocity is +ve, and moving to the left means it is -ve. As you can see in the image, when the car is moving from 2 - 4 s to the left, its velocity is -ve. When it is not moving, its velocity is $$0$$.
Using the same graph, calculate the car's displacement from $$0 \, \mathrm{s}$$ to $$2 \, \mathrm{s}$$ and from $$2 \, \mathrm{s}$$ to $$4 \, \mathrm{s}$$