There are two ways to add buttons:
When you set the content type as Button, the "Create button" window will open. You can label your button here and set a link as a Call-To-Action.
If you'd like for your button to send an email use "mailto:" followed immediately by the email you want to send to.
As an alternative, you can select one of the pre-defined links:
Once the button block is added to your newsletter, you can edit its properties:
If you want to insert a button directly into a Text block, use the button in the
text editing menu.
Once you click to insert a button into text, the dialog below will open.
You have the opportunity to set the link, text and other properties for a button.
When embedding a button to a text block, you can only edit its properties while inserting. If a button is added as a standalone content block, you can edit its properties at any time.