First, create all the form fields that you want to associate with a condition. In this example we will show the email field only when the visitor selects yes for "Would you like a representative to contact you via email?"

Next, select the conditions tab and create your condition and:

1. Add a new condition
2. Select a condition on the triggering field
3. Select which fields are shown or required based on value chosen for the trigger field
4. Add additinal conditions, as needed
5. Save and test

This is what a visitor would see using the previous example.