You have to do that through a custom theme. Maybe you already have one? If not, follow Manton’s instructions here. Then:
-
Follow this link or go to Design → Edit Custom Themes.
-
Click on your custom theme.
-
Click on the template containing the
<head>
section. Probablylayouts/partials/head.html
. -
Add your
<link>
element to the template.<link rel="me" href="https://example/yourhandle" />
-
Press Update Template, wait for your site to rebuild, and celebrate.