Cleaner Crew

[beginner01]

I know that you should only add like 1 fish or so at a time so should you only add 1 part of the cleaner crew at a time or is it ok to add them all at once? Also, this is really stupid but do you have to acclimate the cleaner crew?

 

[ktbug]

what excatly do ya'll consider a cleaner crew?
katie