First, action (from Mexico).
Then, talk.
But... it probably doesn't matter.
Even if Mexico actually does something to slow the flood of illegals during Mr. Trump's time in office, eventually he'll be gone, and it will be back as it was before.
The one thing that will "keep on working" after this administration leaves office is a solid border barrier, a wall that "is there" and will remain there, passively serving its purpose.