at first hand
Directly. As a teacher, I've seen at first hand how reading can change children's lives.
at first hand
Directly from the origin, without intervention or intermediary. For example, I prefer to hear his criticism at first hand, rather than having it passed on by my boss . This phrase uses hand in the sense of "person" (coming directly from one person). [First half of 1700s] Also see at second hand.
at first hand
directly or from personal experience.