Using Text Entry fields as variables to advance

I am working on a software simulation and in one part the learner needs to enter a specific string in a text entry field in order to advance to the next text entry field (there are 3 here). In RL the user would normally enter the content and hit Tab to get to the next one, but I know that won't work with the accessibility controls (will it?) so I'm using the Enter key instead. I have put each of the 3 text fields in a separate layer with its corresponding instructions. So the order of events should be:

1. Layer 1 appears at specific audio cue point of base layer.
2. Learner enters text in Layer/Entry 1 and (if Text Entry matches correctly) clicks Enter and Layer 2 appears.
3. Repeat Step 2 for Layer 2 and Layer 3. On Layer 3, pressing the Enter key if the text was entered correctly transitions to the next slide.

However, Layer 1 won't transition to Layer 2 and beyond. I think my problem may be in the wording of the Trigger. Right now the action to proceed (to another layer or slide) occurs When the User presses Enter after clicking (the current textbox; anywhere on the layer; etc.--I've tried everything) If, of course, the text value is correct. (...The trigger interface is confusing because it forces me to determine When the action occurs based on what has just been clicked, rather than by tapping Enter with the right text value.) Please advise.