Lippert Hydraulic Purge - How To Do It?

The link provided the air purge .pdf document which is great. Thanks! Since I am also trying to remove the contaminated fluid (containing dirt/particles that may be keeping the control pistons opened), I need a "how to" document to completely remove the existing fluid, flush and then refill the system. During the process I will also dismantle and clean the control valves, check o-rings and springs, reassemble and then fill and perform the purge process on the system to remove any air. Any feedback on a process to remove and flush the old fluid? Thanks again!