Benghazi was not an impeachment case.
I've reread the Constitution three times now and it says the following about impeachment:
1) The power to impeach rests with the House (Art. I, Sec. II, clause 5)
2) The Senate shall conduct a trial, the Chief Justice will preside, and it takes 2/3 to convict (Art. I, Sec. III, clause 6)
3) The sole penalty for impeachment will be removal from office and disqualification from future office. They can't send anyone to jail. (Art. I, Sec. III, clause 7)
4) The offenses for which the President or other Federal office holder may be impeached are: Treason, Bribery, High Crimes or Misdemeanors (Art. II, Sec. IV)
And that's it. Nothing like the detailed process steps you are describing is to be found there.