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Easy enough job for many but you don't do it often unless your in the trade.
There are more then a few youtube videos on the subject.. worth doing rather then stuffing new parts no matter where you get them.
Here are a few.. worth the eductional time..
https://www.youtube.com/watch?v=ts6vX8csaTA
Using a Power steering Filter.. https://www.youtube.com/watch?v=-dpA4gy_2Ug