That Satan was an archangel or the highest ranking angel is a common misconception. It is often stated just this way in church doctrinal statements. But in the KJV the beast called Satan is said to have been a cherub above the throne of God. He was a fifth cherub, the one representing before God the class of reptiles. As such he was the serpent, the most subtle of all the beasts of the field.
In the very chapter where Paul tells us the serpent deceived the woman, he tells us Satan deceives by transforming himself into an angel of light. Theses slides, Satan: His Beginning and End, deal with where he came from and where he will end up. They are not a study of his methods and practices.