How to manipulate models

I am new to 3D CAD but have managed to construct my artist’s concept. Easiest to think of it as like playground equipment. I need to include a child for size comparison and better visualization. There are such models available but I have never worked with them. Where can I find info on how to bend, pose, articulate 3D human models? I’ve played with it and gotten nowhere yet. Thank you.

Hi Don - I think over the years Poser has been a useful tool for getting 3d figures -

I don’t know if that is still a favorite for Rhino users in the real world though.