There are two views when editing the content of your webpage:
- Visual - easiest to see and work in for layperson
- Text - coding and style view, more advanced view for editing and embedding code like iFrames
To embed an iFrame like a google map into your webpage, you need to click on the Text tab in the top right corner of the content editing screen, and paste your iFrame code into the area you want it.
Then when you change your view back to Visual you will be able to see the content of your iFrame like this.