The Google map is a simple custom module.

1. Go to Extensions » Modules Manager
2. Click on New
3. Select a Custom HTML module
4. Click Source Code
5. And insert the html code from the Google Map to the Custom Output field

And please make sure that you have insert a max-width of 100% like this:

Please make sure, that you have disabled the Joomla Content Editor ( Tiny or JCE), otherwise you html code be deleted or cleared by your Editor.

1. Go to System » Global Configuration
2. Default Editor = NONE
3. Save