Would you be so kind to explain the meaning of the phrase "on this one" please.
A little story:
A man had a lot of tasks in a school, but he didn't do them properly. He made a mess of them.
Another man said: "Follow me on this one."
In this context does "on this one" mean "Now (from now on) you should do it as I tell you", or does "on this one" = now?