Since you didn't mention what exactly you wanted to know, I'll just list everything. Forgive me if it's a bit low level for you.
Things you'll need
1) 90+% Isopropyl alcohol or 95+% Lab grade ethanol
2) Thermal Paste (I use MX4 these days)
3) Anti-static wrist strip (nice to have but not essential)
4) Q-tips
5) Dental Floss (possibly)
Directions
1) Power Down PC
2) Switch PSU switch to off or "0"
3) Unplug PSU from wall
4) Gently remove the cooler with a slight push or twist.
5) If it won't come off easily, soak the dental floss in the IPA and then place it at one corner of the cooler and gently saw it back and forth until the cooler comes off.
6) Stick the Q-tip in the IPA and thoroughly remove the paste
7) Once both CPU and Cooler are clean and dry, apply a pea sized amount of thermal paste in the middle of the CPU and put the cooler back on
8) Secure cooler to motherboard
9) Start computer and check temperatures using the program of your choice
10) If everything is good, grab a beer and consume it.