I can't help you directly, but here's the documentation.

Here's the steps, pulled directly from the link. Linking a Button To add a link to your button:

1. Click on a button, and a toolbar will appear above it.
2. Click the Link icon in the toolbar. The icon looks like an actual link you would find in a metal chain.
3. Search for an existing page on your site or type/paste a URL.
4. Click the “Apply” button.

Here