I added this into the FAQ
How does officers' automatic recruiting function work?
The officers recruit volunteers every 72 hours. 1 offcier can basiscally get 8 recruits(1 squard) everytime, general can get 16.
The final recruit number will be effected by that center's public order, the melee weapons and pistols storage in that center, and the center's type.If you have built a barrack in that center, it can give the officers 40% more chance to recruit better volunteers.
After the recruitment, that center will get the newbies(only melee soldiers), lost a little prosperity according to the recruit number, and your armory will expend the weapons they needed. The player probably won't recruit any man from that center in the last few days.