SharePoint Power BI web part

Hello.

I have been able to use the new power bi preview webpart on a site page inside a SharePoint online site. This was the article I followed - https://powerbi.microsoft.com/en-us/blog/integrate-power-bi-reports-in-sharepoint-online/

However, I would like to add this to a page with a custom layout on SharePoint publishing page. I don't believe this is considered a modern page as it is not a site page as mentioned in the first paragraph.

How can I do this?

Thanks