Once installed, there are 2 main items you need to take care:
1. Alert Message text field
This is a text area field with length 255 characters. Message in the popup alert will come from this field.
2. Popup Alert S-Control
Although S-Control has been deprecated, but you still can use it.
You just need to add Popup Alert S-Control into the object page layout, while the Alert Message field do not really need to be show in page layout (unless necessary), or you can set it as read-only, so only partial user able to edit it. You also can populate the message to display using workflow, process builder or apex code.
Type: AppExchange (Managed Package)
Publisher: Riptide Software
Blog last updated: 23 Mar 2016