I had a CPC1100 for three years and neither I nor the previous owner ever needed to collimate it.
Several experts checked it and all agreed it was perfect.
However, not all scopes are this lucky.
The first thing is make sure you really need to before adjusting anything.
The defocus star test should confirm your diagnosis.
From memory, collimation is described in the manual.
Or try this link to the Celestron site:
http://www.celestron.com/c3/support3...articleid=1974
Hope this helps.
Al