In this step you solve the bottom corners. There is two manuvers you have to know for this, one manuver switches the front right bottom corner with the front left bottom corner. The other manuver rotates 3 of the bottom corners counter clockwise. The first thing you want to do is get all the corners in the right possition (they don't have to be twisted correctly). Then you do the second manuver to roatate the corners till the corners are solved.

So first start by looking for 2 adjacent corners that have a color in common other than the bottom color, then turn the bottom till those two cubes are infront of the face of the color they have in common. Now if the cubes are in the right position then flip the cube to the other side and look at the other 2 corners and see if they are in the right spot. If they aren't in the right spot you have to switch them by doing the manuver below. Once you get all the coners in the correct spot scroll down to see what to do next.

Now that you have all the corn cubes in the correct spot you have to rotate the corners until the corners are solved. If you only have one correctly twisted coner, put the corner to you left and do the manuver below. If you have 2 correctly twisted adjacent corners put them to the back and do the manuver below. If you have now correctly twisted corners or have 2 diagnal correctly twisted corners choose any face and do the manuver below.