Ive tried giants but they are only greater souls can trap dragons. what is a grand soul in this game? is it dadera? if so i am not up to them yet. my enchating is close to 100 but cant enchant no grand souls in me grand gems

The grand souls probably wont appear until higher levels, in oblivion certain monster's that started as greater souls would level scale to become grand souls. I find it much easier to trap human's etc into black soul gem's (found 1 so far, hoping we can create a lot a la oblivion )

Mammoths can have them. They also have greater I think.