He said to them
"Joseph said to his brothers"
No, you have come to see the undefended parts of the land
The full meaning can be stated explicitly. AT: "No, you have come to find out where we are not guarding our land so that you can attack us" (See: rc://en/ta/man/translate/figs-explicit)
"12 brothers" (See: rc://en/ta/man/translate/translate-numbers)
See, the youngest
"Listen to us, the youngest." The word "See" is used to emphasize what they say next.
the youngest is this day with our father
"right now our youngest brother is with our father"