Jratcliff

I just got one, today!
It was on the floor at the quiltshop and I fell in love. It worked beautifully, even in my hands. Absolutely no problems whatsoever.
They boxed it up and I brought it home. Took it out of the box and got it set up. Still had the same bobbin in as at the shop. I threaded it as per directions, never touched any settings, and I now have a horrible mess. The tension is way off and I can't seem to get it set right. I am at my wits end right now.
Does anyone have any suggestions?
According to the book you only play with the bobbin tension, and if that fails you can start with the upper, but it doesn't seem to help.
I don't know what I'm doing wrong.