Hi !
Don't worry, you're not the only one, it's not clear enought. I will add a small description in the build mode on building to know what they do, because there is actually a building to automate their work.
Build a "Worker Sanctuary" and follow the "?" on his special scene and you will can automatize everything.
I suggest strongly to get at least 3 workers assigned here, with hight obedience to ensure no loss.