The video is short, just over four minutes, well worth your time, but the link also has stills showing the process. It's just fantastic to watch as they perfected the suit and the movements to make the creatures so believable. The thing that continues to astonish me is that while Jurassic Park is almost 20 years old the special effects largely stand the test of time. (Which, in my opinion, is partly due to the practical effects... digital effects can age poorly in a way that practical effects often do not.)
There is also footage of special effects superstar Stan Winston clowning around with the raptors. You are missed, Stan.