There are different ways to handle a broody hen, assuming you want her to hatch and raise the chicks herself.
You can let her hatch with the flock, it's what I do. After you have determined she is really broody (my test is that she spend two consecutive nights on the nest instead of roosting in her normal spot), collect all the eggs you want her to hatch and mark them. Clean out all the old eggs under her and dispose of them. You can crack each of them in a separate bowl and see if you see any development to see if they are good to eat. Some people do. This way all the eggs are started at the same time which is important. You don't want a staggered hatch where some eggs hatch early and some never hatch because they started developing too late. No matter which method you use, start all the eggs at the same time.
I mark mine with a black sharpie. After you start the marked eggs, check under her each day after the other hen shave laid and remove any that do not belong. As long as you do this every day the eggs are good to eat.
The hen should leave the nest occasionally to eat, drink, and poop. I have had a broody hen leave the nest twice a day for over an hour each time, typically in warmer weather. I've seen a hen leave her nest once a day for only 15 minutes, typically in cooler weather. I never see some broodies off the nest but I know they are leaving because they don't poop in the nest. I trust my broody hens to know what to do much better than I know.
If you decide to relocate the hen, build a pen so she cannot get back to her original nest. In that pen you will need a nest, food, and water. A little room for her to go poop is good. She should know by instinct not to poop in her nest but her instincts don't cover food and water. You may need to clean things regularly.
The biggest risk in moving a broody hen is that she will break from being broody. I find it helps to move them at night into a fairly dark nest. Move a few old eggs with her but swap them out for the fresh eggs so they are all started at the same time when you are sure she has accepted the move. She will probably want to return to her old nest at first but be patient and give her time to accept the move. It's probably best to not give her a lot of room in that pen.
Good luck!