Embed SPFx web parts into CMS365 pages, and have them resize automatically. The embed file picker will allow you to simply select the site pages library and select the pages you with to embed.

Add administrators, designers and authors to your CMS 365 site, you can assign roles by adding people directly or assign a role to the built-in owners and members groups of your site.

Once the content has been loaded, you will be prompted to map authors from your on premises environment to online users. Authors that share a similar login will be auto-detected.

Select your file and click the "Select" button to insert an embedded frame to this file.