My users will need to type in a specific code and then hit the tab key to get
to the next field. I'm using the input field and I thought the keycode to check
if they have pressed the tab key. Can someone tell me if I'm on the right path?

Try somehting like this: put it on an invisible button off the stage, answer1
would be the input text box, right and wrong could be frame labels where you
give feedback.

on (keyPress "<Tab>") {
if (answer1 == "xyz"){
gotoAndStop("right")
} else {
gotoAndStop("wrong")
}
}

Good Luck,
Rob