I'm no expert, but I belive the process is something like.
Manufacture decides on what character to make and what pose, what materials, and so on, probably making concept sketches first.
Then when when it's decided, a sculptor sculpts a figure out of a clay and presents it for approval, changing it where need be.
After they are satisfied with the model, I believe they'd make a mold of it, but covering it in a substance that would take it's shape then harden, they'd then make another model using that, a prototype, not clay buy not finished, they'd use that to decide if the fig is good to go and how they'd paint it.
They'd take the fig off to get photos taken, and and box art done, then using the mold and programing some robots on the assembly line to paint the things, mass production starts, although I'm sure it's mostly made my machines, I bet there's someone somewhere on the assembly line, at least making sure it's all going okay.
then there's the matter of letting stores and suppliers know about it, and taking orders, shipping them out in bulk amounts to the business.
again, this is just what I believe it to be like, for all I know, it might just be all magical fairies.