UI Components / Simple Modal
In your Backendless App, go to the Marketplace -> User Interface tab and install the Simple Modal componentInstall the component to the UI Container of your choice

Simple Modal

Simple Modal is a designer component of Backendless UI-Builder
that allows you to add a modal dialog box.
You can add "Alert" to notify you about certain information,
"Prompt" to get information from the user,
"Confirm" to get confirmation at user for some actions.

The component based on external Simple Modal.

UI Components / Simple Modal