To use the Google Map service you must have a Google account and ask for an API Key.
First, login here : https://console.developers.google.com
Follow the steps to create a project for your website and ask for a "Server Key". Once you have your key you must activate it.
Now you have your KEY to load a Google Map. But you can still not search for locations. To use the automatic geolocation (which retrieves the Latittude and Longitude using a Location name), you must also activate the "Google Maps Geocoding API"
That's all, you can know copy / paste your API Key given by Google into the field in Page Builder CK.