How to set the slide to change only on a click or hitting the "enter" button

Your question is not clear at all to me.

D&D slides do pause by default at 1,5 secs, have a look at:

Pausing Captivate's Timeline - Captivate blog

When the user clicks on the Submit button, and the answer is correct, the action On Success defined on the D&D panel is done. If you have only one attempt, on Failure the action On Failure will be executed. If there are multiple attempts, the user will be able to retry the D&D. What do you want to change? The Submit button can have a shortcut key assigned, which can be Enter.