I am completely lost on how to use the various body shapes in my game.  I have the fat family meshes from melodie9 already and those look pretty good in my game - at least with the clothing that I was able to find and download.  I would love to use the body builder meshes as well, but there are a lot more options presented and with the base meshes and skin tones forum it was stated that I would need to download all of those files.  Why do I need all of those files for a single sim?  I didn't have to download all that stuff for the fat family meshes so I think I'm misunderstanding something there.  Everything is spread out across different threads from retired creators so it seems very confusing to me.  To keep it simple, if someone could tell me what base files - not counting the clothing - that I would need for a male and female sim to be played from child to adult using the body builder body shape, I would be very grateful.  I do plan on using the body shapes on more than one sim eventually, but I want to test them out on individual sims first.

I am aware that clothing files are separate, but I am looking for something specific with clothes as well for the fat family as well as the body builder shape.  I play a highly customized game based on Harry Potter.  I love the idea of being able to create some of the "larger" characters like Vernon and Dudley Dursley, Hagrid, etc...  The clothing I use for my students is recolors of the robes created by mia86, which go from child to adult for males and females.  I also use recolors of the trenchcoat for Quidditch robes - teen through young adult - a link to the converted trenchcoat for female teen and young adult was included there. 

I've seen a lot of the regular maxis outfits converted for both the fat family and the body builder body shapes, but I have not found any conversions of those custom clothes for the fat family or the body builder body shapes - except for the trenchcoat for the male adult and teen body builder.  Nor have I found any instructions on how to do such conversions myself.  How are these conversions done?  And if that involves meshing, is there a tutorial explaining how to convert a regular mesh to one of these body shapes?

Thank you