Submitting an XML sitemap to Google allows your pages to more easily and quickly be recognized and crawled by Google, which makes them more likely to be found on a web search.
Google will not allow you to submit anything for a site that you do not own, so you will first have to verify your subdomain for Google to recognize your IDX Broker 'property'.
Once verified, you can log in to your Google Search Console and select the subdomain that you are using for IDX Broker to start.
Inside your Google Search Console, on the right-hand side you will see an option called “Sitemaps”. Click on the chevrons to see all submitted sitemaps, or submit a new sitemap.
Click on “Add/Test Sitemap” to submit your sitemap file.
On this page you can see which sitemaps are discovered by Google or which sitemap files have been previously submitted.
Log in to your IDX Broker account and navigate to Designs -> Pages. Click on 'Link' next to your XML sitemap to find your sitemap link.
Copy only the path for the XML link from your IDX account. For example; idx/sitemap/xml/6357v871q2 Paste into the box in your search console and click 'Submit'.
It might take some time for you to see all your pages indexed. Be patient and please do not submit your sitemap multiple times, as this will slow down and restart the process with each submission.