In order for the application to receive notifications from the system, you must activate the checkbox located next to Chat Locator in Configure - Sound and notification - Notification access, at Android configuration.
First time use will shown a message indicating that notification access is not enabled. Click on the HERE link to go to Android access notification settings.
Android access notification will show up. Click on the checkbox next to Chat Locator to enable the program to read system notifications.
Click OK on the dialog box to confirm.
Go back to the app to check that everything is OK on the Install Tab.
On the Config Tab enter a Key and Save it. The string will be checked against the WhatsApp messages you receive. If match an SMS is send to the person who sent you the message with your last location.