Last week I got some videos of Sierra trying to crawl. It's really funny and cute. They will also give you a good example of her screaming. Especially the second one. Although in that one it is more mad screaming than for fun. (please try to ignore the drool and spit up on the blanket-that's prettty much all she does these days)
Isn't her little rump up in the air so cute? Her little legs are trying SO hard to move!