Just by looking at it: Push the first, the second and the fourth (from highest to lowest) boxes one field to the left, then push the third one up one field so you can move on to the second row. Now push the second and fourth one to the left, so you can push the third one up again.
Since you are now able to move freely finish everything but the third row from the top, since this is your open corridor to make sure you can end up with the last two boxes both on the right side. Then you can end it from there by pushing them to the last two spots.