Triggers for keyboard navigation- branching scenario

I'm trying to make this course (my first one!) accessible by keyboard navigation only. I've set the focus order so that users can press tab to move through the different options. I'm trying to figure out how to create a trigger so that when the user presses enter when they've selected their answer, it takes them to the appropriate slide. Right now, when I select jump to slide or show layer when user presses a key it's adding a condition- after clicking on this slide or clicking on object. I don't want them having to click on any objects- that's the whole point of keyboard navigation, right? What should I do? I did create another state- the object when selected- and had thought to create triggers like jump to slide when user presses enter if object (envelope) is selected but that doesn't seem to be working either. Are there any workarounds for this? Or is there something I'm doing wrong? I can upload more attachments if needed. 

Thank you so much!