I have 19 budgies and 10 are free to fly the room all day but sleep inside their cages. They either go back inside by themselves or I put them back in on my hand or on a stick perch. Some are harder to get back inside than others and make me "chase" them a bit before they stay on the stick while I put them in. They aren't scared but don't want to go back in.
Is she finger tame? If not, I suggest you fingertame her imlnside the cage before you let her out or it will be very difficult to get her back inside without grabbing her and scaring her.
Next, your budgie needs to learn the room. When she first comes out she will probably fly very erratically and is at risk of flying into something and getting hurt in addition to being difficult to get back inside. I suggest slowing her down by having a very minor wing trim on both wings. The goal is to have her be able to fly but not too high or too fast. Basically, she would slowly flutter to the ground rather than landing atop doors, etc where she would be hard for you to reach. It will be much safer for her and much easier to get her back in her cage.
With trimmed wings, she will be able to fly a little and perch on top of her cage or on a playstand and when it's time to put her back inside you can use a stick perch or your finger.
Some people strongly disagree with any wing trimming but your budgie has never had full free flight so she won't miss it, and she will be safer. Once she learns the room and is easier to get back in, the wings will have grown back and you will probably never need to trim again.
This is assuming there are no dogs or cats that could harm her. A budgie must be able to escape from predators quickly and she shouldn't even have slightly trimmed wings If there are any dogs or cats around.
Good luck!