In order for the application to receive notifications from the system, you must activate the checkbox located next to Chat Buzzer 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 Buzzer 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, expand de New group item, enter the WhatsApp group name you want to monitor. By default New groups have a Test word defined. Use Edit button to add/change/delete words. Click on Select ringtone to choose a system tone to alert you. Finally click on Create group to add it.
Create as many WhatsApp groups as you like and add as many words to them as needed.
Then ask someone on the group defined to enter one of the words defined and check as the ringtone defined will sound.