By using Composer!
Because this project is private and host on Gitlab private package repository you must some extra steps to install this on your project.
First add repository to your composer.json
composer config repositories.abedi/financial '{"type": "composer", "url": "https://composer.jeyserver.com/abedi/financial/packages.json"}'
Add Jeyserver's Composer repository and Gitlab into your composer.json
composer config gitlab-domains composer.jeyserver.com git.jeyserver.com
Make a Personal Access Token in Gitlab with minimum read_api permission and create an auth.json file with that:
composer config [-g] gitlab-token.git.jeyserver.com <personal_access_token>
composer config [-g] gitlab-token.composer.jeyserver.com <personal_access_token>
And as final step set the required package version:
composer require abedi/financial:<version>