Gaming

So I finally decided to get round to playing the original half life seeing that it was recently free on Steam. But I’m stuck at the very beginning! I’m doing the part where you push some crystal into an “anti-mass spectrometer” as part of some experiment my character has to do, but it keeps going wrong. I luckily saved the game just before this part, but every time I start it again the test goes wrong. How do I pass this part? I’ve heard good things about this game, but I can’t get past the first real hurdle. Please help (hopefully this description helps)