You could look into Mudbox,...sold by Autodesk. I have an older version 2009. You can sculpt a mesh with their software. The learning curve is a little high,..but anything worthwhile is. They have prebuilt human meshes to start with.
However, if you are going to pose the character, you're going to have to learn how to "rig" the object. You'll have to export the mesh into Cinema4d or Maya, or some other program and build the skeleton,..and morphs etc,....
I'd suggest to start at manipulating simple primitive objects, like cubes and spheres, building simple forms, then applying a hypernurbs,.....
Youtube and Vimeo have some great tutorials.
Best Wishes!
Rob