Put two squares together like this for one side of the bus.
Do the same with two other squares.
Stand both sides up and join them with another orange square.
Join the other two ends up with a red square to make a box. This square is at an angle as it will be the front of the bus.
Make the front using some smaller rectangles.
Use two orange rectangles to make the top of the bonnet.
Use larger rectangles to close the top of the truck or bus.
Finally, add some wheels to the side.