CI/CD Gitlab CI file for PHP projects that would test, build, and deploy

Need insight on creating a CI/CD Gitlab CI file for PHP projects that would test, build, and deploy, I've gone thru the doc, yet can't quite grasp and put together a file that would do all three stages. Most of the sample files available in Gitlab docs for CI/CD are Ruby related or some other language except for PHP.

• Could you provide a sample Gitlab CI file for PHP that work for all 3 stages
• If possible make deployment to be triggered by a Deploy button.