Just have to crank the wheels from one side to the other while applying the brakes. Be careful the fluid will foam up when you are doing this, but this basically how you do it. If you can jack up the front end then it is a little easier but not really necessary.
The accepted way is to remove the non-pressure hose from the brake hydroboost and just rooting it to a bucket. Then have somebody tap the brakes while it pumps out and you keep topping up the power steering reservoir. Not great but most do it this way. There is a utube video on it.
The video is for a 6.0 but they all are basically the same system. The 6.4 will just be more work because everything is so packed in. Let us know how you make out.