Craft Edge

I just purchased a used Expression. I already have one and love it. What steps do I need to take to get this machine to work with my current SCAL2?

I'm not an expert on Cricuts, but the first thing I would do is just test it out with a simple shape. I doubt if you can have both Expressions plugged in at once via USB. So, maybe start with a very quick simple shape and verify it works with your original Expressions. Then unplug that one, plug in the new one and repeat to see if it works.