Welcome @Anna_Western1 
Since you have all the content already created, you’ll need to do this through some automation tool like Make (Integromat).
Make can connect to your CMS, grab an item, and send whatever content you like to most any email tool you’re using.
You can setup Make to run on a scheduled task, like once per day, once per week, etc… so it does this without you needing too.
Hope that helps!