Hi Jim,
it is rather simple. Remove the top cap fron the damping rod, the spring.
Pour away the oil.
Use a impact driver to lossen the compression body at the bottom of the fork.
There will be some oil left, so be careful.
Remove the cartidge and "pump" the excess oil inside the cartidge.
Clear all the holes and passages way.
Install it back the way you dissemble and pour in the recommended oil level and you are done.
:)