Correct
So you know how to play the game? Ive never been able to catch more than 8 or so people... stupid traps never work for me!
You hit the traps as soon as the trap bar gets into the red. At certain points in the game the access code (which is a color, listed above the bar) will change. You have to hear the characters say what the color change will be. There's maybe three or four changes total in the game. When the vampires start sounding nervous about how the night is going, that usually means their dialogue is going to head towards changing the code. There are Night Trap walkthroughs online that list the exact times that augers and code changes happen. It's too hard to actually follow that while playing the game, but if you just use it for the code changes you shouldn't have a problem.
Or, if you have the time,
FMV World has a video called "Night Trap the Movie" (it just says Night Trap on the site) that has all of the cutscene footage, since you can't really watch it during the game. It's a good way to see the entire thing unfold, which also lets you see when important things happen. It's a simpler alternative to just playing the game over and over and over to keep track of this stuff. It doesn't let you see the augers, of course, but it's not hard to catch them if you know what's going on everywhere else.
Once you know the general flow of the storyline and know when the trap changes come, Night Trap's really not that hard to beat. The hard part is beating it with a perfect score, which I think is downright near-impossible. But if you do, you get to trap Dana Plato, so it's all good.
edit: Oh, and it's important to note that there are some augers you just can't trap. You'll know if it's untrappable if it doesn't add to the auger count.
And it looks like FMV World also has a perfect run video, which I had forgotten about. It's really easier to just keep playing the game than try to memorize THAT though.
One more thing--skip the intro cutscene, it tends to help you get going.