Because I tend to mess things up l,ll ask here. Please keep the answer simple and assume I don't have a clue, which I don't. A) how many m/c,s can it be used on per account, that is. B) how to remove from one and add to another. My granddaughter did it for me, she can't recall how , it was done years ago. I feel is an app to add on , so do I just remove it ?