It is possible to let a question appear when a certain answer is given on a previous question. 
With this option it is possible to show participants questions that are relevant for them.

Open the registration form by clicking on Registration form . 

1. Add the question that you want to show after someone gave an certain answer. 

2. Click on the gear icon to open the settings from this question.

3. Behind question will show if you will see when the question will appear. Automatically you will see ; if : participant is registering is chosen. Click on change to modify it. 

4. You can now select the answer to the question where it should follow up. 

5. Click on apply

6. After ´question will show if´ you can now see when the question will be shown

So you get the following; when a participant chose speaker, he will see the question about what date he wants to go.