If you have 2 adjacent well permuted corners- turn the upper face once clockwise (U). That move will reposition the corners into a situation which only one well permuted corner will remain while the other three corners needed to be rotated counter-clockwise. Now just execute the algorithm above, and by this single execution you actually completed this step (remember to execute this algorithm from the correct angle – when the well permuted corner is on the back right. see algorithm image above).
Keeping white on top, turn the cube so that a different colour face is toward you. Follow the above instructions again. Repeat with the other two faces until the white cross is complete. This step is quite intuitive; you can do it for sure but it does take a little practice. Just move the white edges to their places not messing up the ones already fixed. Rubiks Build It Solve It Review
If there are no more edges left on the top layer, then they are probably either inserted in the right place but flipped, or inserted in the wrong place. To get an edge out of somewhere it shouldn't be, just insert one of the yellow edges into that slot. This should get the edge out and on the top layer, ready for you to use the above instructions to insert correctly. Rubix Build