Paste the code right before the closing body tag of every page.
Replace www.mywebsitedomain.com in the code with your custom domain
After you install the script on your site, open your Offerbox dashboard and click "Configure" in the navigation menu.
Find Website settings and add your custom domain.
Your website domain must match the value here. Most websites these days use multiple domains. At a minumum, you have a domain with "www" and also a root domain as shown below.
Therefore it is important to configure a primary domain for your website and add redirects to the primary domain. Offerbox only accepts a single domain. In case users visit your site with other domains and there are no redirects to primary domain, Offerbox will not be visible to the user.