The ngex-dialog is published on the npm. The library works for applications with the Angular version 8 or above.
Run npm install ngex-dialog to add the library into your project directory, or add "ngex-dialog": "~12.2.0" to the package.json file and then run npm install to update the existing package.
To see how to use the dialog in details, please go check out the article An Angular Modal Dialog with Advanced Functionality and Easy-use Features.
The sample applications with the article also include those that directly use the TypeScript code of the modules and components in the ngex-dialog directory.