Doing some google searches should help, or even using the search engine here for old threads.
The timing when to divide your bamboo is important. You'll want to do it before it shoots, but it's probably too late now so if enough time has past since shooting it maybe alright. You'll get healtheir divisions(I've found) if you wait until spring. Also you can do strictly rimozome divisions in the spring, and end up with a ton of new plants.