Oh no! That's my bad, I think it's just very non-intuitive that you have to use the number keys to pick your dialog choice, and sometimes there's only one option, type "1" on your keyboard to have your character say the option 1
When there are multiple options, you can type the appropriate key to pick a different option
Sorry I shoudl have playtested this a bit more, hopefully that gets you unblocked to progress further!