First, create a uCoz Google Maps widget on Common Ninja.
On the widgets catalog, find the Google Maps and enter the Editor.
When you're done creating the Google Maps widget, click on the Save Changes button at the right top corner of the editor.
If you don't have an account on Common Ninja, you'll have to register first.
When you're ready to add the Google Maps widget to your uCoz website, click the Add To Website button at the top bar of the Editor.
On the window that opens, click the Copy Icon to copy the widget embed code. In the next steps, you will paste this code into your uCoz website.
Now, let's head to your Ucoz website's editor.
In the Ucoz editor, click the Edit HTML button of a page you wish to add the Google Maps.
In the Page editor, simply past the Google Maps embed code you've copied before.
Click the Save button at the bottom of the window, to save your change and close the window.