First, create all the form fields that you want to associate with a condition grouping multiple fields in fieldsets. In this example, each checkbox triggers a separate fieldset of information, in the event all three checkboxes are checked, all the fieldsets will be revealed.

After creating all the fields and fieldsets associated with the form, select the conditions tab and:

1. Click add a new condition
2. Select the desired 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

Here is a working demonstration: