PHI Build is the tool you want to use, it allows you to setup your bones in a hierarchy (parent/child) relationship and then creates a bone structure through Poser's File/Convert Hierarchy File...then you enter the setup room and move the bones into position.

I use this mostly for customized figures that I've created. There is no need to use this if you are creating conforming clothing as the internal tools within Poser can do that automatically.

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