Complex sentence: The plan was for the attack to begin north of the Psel river with 3rd SS Panzer division "Totenkopf" driving northeast to the Karteschewka-Prokhorovka road, then striking southeast to assault the Soviet positions at Prokhorovka from the flank and rear.
Split into simpler sentences: The plan was for the attack to begin north of the Psel river with 3rd SS Panzer division "Totenkopf" driving northeast until reaching the Karteschewka-Prokhorovka road. Once there they were to strike southeast to attack the Soviet positions at Prokhorovka from the flank and rear.