First things first, we need to know what call script is being used by the campaign you wish to run.
To do that, navigate to Manage Campaigns > Campaigns, highlight the campaign in question, and edit it. In the example below, we can see that the campaign is using the script "New Message Script".
To test this script, navigate to Call Scripts > Call scripts, highlight the script by clicking it, and then hit the "Test" button. You will need to input a valid 10 digit phone number in the "Phone number" field, this will give you the ability to test the message.
In the scenario where you have a different message for customer vs. voicemail, you will need to test twice. To get the customer message, simply say "hello" and wait. To test the machine message, you don't need to say anything. You can also test the linkback feature and agent message by adding your office number in the "Link Back number" when testing.
If we want to see what messages this script is using, click "edit" instead of test. In the example below, we can see that this script is using the "new" message for customer and machine.
If we wanted to see the message steps for this message, navigate to Call Scripts > Messages, and edit the record in question to view and change the data.
If you change/update a message you will need to resave any call scripts this message is attached to, otherwise the call script will still use the old message.