My new Wheels (me vs. I)

I might have missed the Book Bloggers Convention but I got a sweet new Guardian walker! Score!

This is Siena and me testing out the new wheels.

Incidentally, how do you know when to use me and when to use I?

Pretty easy, actually, just take away the second person so you're alone in the sentence. I know not to say This is Siena and I testing out the new wheels because if I take Siena out of the picture I would have This is I testing out the new wheels.

No good. Real bad. But sure makes it an easy one to figure out, eh?