To keep this from happening, astronauts use tethers. Tethers are straps or cables that are used to tie things to the space ship. She can't just walk. To walk on earth, you need gravity to hold you to the surface. Otherwise, you would just push yourself away from the planet with the first step.
Astronauts use hand holds to pull themselves along.
These are handles that are bolted to the space ship. So an astronaut walks with her hands. That is similar to if you are in a deep pool where you cannot touch the bottom. If you want to move along the wall, you pull yourself along the side. An astronaut does the same thing.