and Welcome To BYC! X2 on check out the Learning Center articles. Here is a great one on hatching. https://www.backyardchickens.com/a/hatching-eggs-101 Once the eggs are on "lockdown" usually around day 18 when you stop turning them and you up the humidity to around 65-70%, you leave them alone, usually until the chicks have all hatched (some people like to take the chicks out once a day or so if the incubator is crowded). Chicks can go several days without needing to eat while they are absorbing the rest of the egg yolk. You do not want to open the incubator during hatch if you can help it because you will lower the humidity and if the eggs are pipped or zipping there is a chance the chicks could get shrink wrapped in the membranes. A hen will not adopt the chicks unless she is broody, and not all broodys will adopt chicks, here is a nice article on broody hens https://www.backyardchickens.com/a/broody-hens and the Learning Center in general https://www.backyardchickens.com/atype/1/Learning_Center
