Read the title,I really need answers
I'm pretty sure you cant assign people to certain jobs
Assuming you have all buildings still set to default priority--change that. Click/tap on building (yes, each and every one--there is no group function for this). Click/tap on the blue bar graph icon. Scroll down until you see 2 horizontal sliders. One is priority, other is job numbers. Slide the priority towards the right (you don't have to go all the way, just amount to the right will do). Do this for each building you want workers to start working at first. Be careful though. If you don't watch it at first, workers from food and water production will switch over, with bad consequences. Just keep an eye on food and water when you do this.