Character Rigging

Despite I read solutions for other people who can’t rig their characters, I can’t understand why I can’t rig mine. I use to export Make Human characters and I’m always able oto rig them. But this one, I edited in sculpt mode, I like the result, but now, no matter what I do, I can’t make it work. I had to move its origin, if it matters. I thought I could upload a file, but it says new users can’t.