Conditional logic allows you to show certain questions (or pages) on your forms depending upon the answer to previous questions.
There are 2 options when creating conditional logic.
1. Conditional page (you can add a page break to the form and then only show page 2 IF certain conditions are met)
2. Add conditions to show or hide questions on the same page
To add logic - do the following:
1. Click Logic on the required form and then click 'Logic'
2. Select either the 'Fields' OR 'Pages' logic option
3. Add logic
E.g. Take a look at the sample form (link below). Here we only show the 'Address' question IF the user selects 'Second option' in question 2.
Here is the login I used: