Some if us let broody hens incubate, hatch, and raise chicks with the flock. Others isolate the broody for some or all of these. What your coop and nest look like can influence which is best. In general the less space you have the more likely isolation is a good idea. A community nest usually isn't great for broody hens either.
If you let her hatch with the flock, mark all the eggs you want her to hatch and start them at the same time. Then every day check under her after the others have laid and remove any that don't belong. As long as you remove them daily you can still use them.
If you isolate her fix up a pen with a nest, food and water, and not much else. Lock her in that pen until she hatches. Make sure she can't get out and no other hen can get in.
If you need more details on any of these let us know, but some knowledge of what your coop, run, and nest look like could be very beneficial.