[nothinghere789]

first hand means you got the info from the first or original source.

[RSZC]

That's an unusual definition of first hand...

Here's Merriam-Webster's:

> obtained by, coming from, or being direct personal observation or experience

These lessons are not from the OP's direct personal observation or experience.

[jandrese]

Isn't that second hand? You interviewed the people with first hand knowledge.