Conditional questions in a form is a handy tool to do many things including making sections / questions in your form visible based on previous answers.

The below video will show how events work in a form;

In the field settings of the triggering question of an event you can see the existing events that have been created, and delete them if they are no longer needed.

On each field that is triggered by an event you will see the lightning bolt icon so that you can see what events are being triggered and to go back and make changes on the event if needed. This helps with troubleshooting any issues with your form flow to ensure that you have set it up as you intended it to.