Hi Peter,
The first thing you need to do is create your sitemap by going to All in One SEO, XML Sitemap and configuring the settings (https://semperplugins.com/documentation/xml-sitemaps-module/). You’ll want to check the Notify Google and Notify Bing checkboxes and select which Post Types and Taxonomies you want included in your sitemap. Make sure you check the Dynamically Generate Sitemap box because this will mean that the sitemap is generated when it is crawled by a search robot and is always up to date. There will be no static file on your server if you check this option which is good because static files can get deleted or corrupted.
Once you’ve configured the settings and clicked the Update Sitemap button you need to head on over to Google Webmaster Tools and submit your XML Sitemap to Google – https://support.google.com/sites/answer/100283?hl=en. All in One SEO Pack does not do this for you. Once you’ve submitted your sitemap to Google then Google will know to crawl it when they visit your site.