How do I change a button's words or where it links to?

In the editor, click the button and the Button or link panel opens beside the page.

Change the Label to change its words. Under Goes to, pick one of your pages, A phone number (visitors tap to call), An email address, or Another website, then type the number or address. Tap Save button. Links to other websites are saved with a secure https address.

Changing buttons yourself is free, and Undo puts the old one back.