You can add a button on your site to take people to another URL or page.
On the right, click Insert panel > Button.
Enter a name. This will appear on the button.
Paste a URL the button should point to, or choose a page on your site. You can also use buttons to add payment links or buy now buttons.
Click Insert.
For more information on buttons visit the Google Sites help center.
Additionally, Google has added new button options. Aligned buttons shrink to fit their text, allowing a button to be narrower than the group containing it.