How can you grab items? for decorating your house? In Oblivion you could do this with Z, what's the new button?

Hold down the "take" button. A for Xbox, X for PS3. IDK how it works on PC.

I know the point where I'm at is that you have to talk to the guy you bought the house from to add things to your house. As for physically grabbing items I believe it's holding the E button over it. PC version.