In order to use some of Google's web tools, you need to verify that you own the site with Google. You can do this by creating a page with a specific name Google provides you, as detailed here. This page describes what to do when you reach step 3 of Google's instructions.
google-site-verification: google27r537d527456q7d.html
<%flags> inherit => undef <%flags>
In order to submit a sitemap to Google you'll have to create it manually and add it as a custom page. Please refer to Editing CSS & HTML for how to add custom pages. The sitemap should be created in the root directory of your site, so that it can cover all the content - for example: www.example.com/sitemap.xml
For help with the format of sitemaps that Google expects, please see Google Webmaster Tools Help for Sitemaps.
In order to prevent the WebXG content management system from adding HTML headers and footers to an XML sitemap, you need to add this additional bit of code to the end of your XML file:
<%flags> inherit => undef <%flags>