Mainwaring opens the secret instructions, and it is clear that he doesn't know how to read a map.

He may also give him secret instructions as to voting upon particular questions.

He must have thought I was actually trying to decipher his secret instructions or whatever they were!

He was proceeding according to secret instructions from the directors in Copenhagen.

Is there some sort of secret instruction involved to which I'm not privy?

I have given secret instructions to someone in your vicinity.

Or did Himmler send a secret instruction to the camp authorities?

I know, but there are also some secret instructions to the diplomats.

A secret instruction to protect this area was issued to Percival's generals.

This was a series of private secret instructions to his successors that he had formulated over the years on how best to rule after him.