Step 1: Tools
- cassette tool
- chain whip
Step 2: Whip it good
Position the chain whip on the 3rd or 4th cog, wrap the loose chain part around the cog, use the fixed chain portion to hold the cassette in place.
Then use your wrench to unscrew the lock ring. You really only need to use the wrench to 'break it.', then you can do the rest by hand.
Step 3: Remove
The ramps on the cogs should face out when you put it back together.
Step 4: Reverse it
one one way.
The lock ring thing has a super thin washer. Don't lose it!
Also grease the heck out of those threads, or it will be a pain to get off.