You need to remove the return line (low pressure) from the pump and put it in a container
Then plan on using lots of fresh, expensive power steering fluid
The best way is to have the front tires off the ground and person in the drivers seat
Have them start the car while you pour power steering fluid in the reservoir keeping it topped off. They need to turn the steering wheel. Once you get nice geen expensive fluid flowing into your bucket, you are done
Your current method will take forever as you are constantly mixed the new and old fluid
Stephen