# All the number ... is 186,400

"The number of the men camped under the standard of Judah is 186,400" (one hundred and eighty-six thousand four hundred.)

# the camp of Judah

This refers to the three tribes that camp east of the tent of meeting: the tribes of Judah, Issachar, and Zebulun.

# They will set out first

"When travelling, the camp of Judah will start walking first" or "When the Israelites leave, those tribes will leave first"