I would use new hoses as well. They are cheaper than a new box and pump.
After you get the pump and box installed, hook up the pressure line, and the return line at the box. Jack the front wheels up and place jack stands under them so the wheels are off the ground.
Unhook the return line from the back of the pump and place in a bucket below. Place a vacuum cap over the return line tube on the pump.
Fill the reservoir with power steering fluid and start the motor. It helps to have someone on the key as you keep an eye on the pump.
As the engine starts, be ready to keep filling the system. The pump will flow fluid through the system. Keep going until you have fluid flowing out the return line into the bucket. Shut the engine off and attach the hose at the back of the pump.
Top off the fluid and restart the motor. Make sure it stays full. Have your helper turn the steering wheel to full lock each way slowly. This will help purge air from the system. Keep doing this until no more bubbles appear in the reservoir.
Check the fluid level one last time and take the Jeep off the jack stands. Take it for a drive on a back road or non busy street. Stop occasionally and check the fluid level.
After you get home and the level is staying the same and there is no leaks, crack open a beer and admire your work.