Can I add a thank you page when someone successfully submits a form?

Yes it is possible to add a thank you page on succesfull form submit. To do this go to the editor first and add a form to your page using one of the plus buttons and clicking "Form".


After you have done this you will have a form added to your page, to read more about al the functions of a form please visit: 

Editing a form element


To add a thank you page click on the button in a form, and click on the enveloppe icon shown in the image below:


Here you have two options, the first one is to add a URL. This is the URL that the user will go too after a successful form submit.

The second option is to add a message, this is just a message that will be shown after successful form submit.