How can I show this project as an article in Past Projects?

In Past Projects, we only introduce the Project which the Client give us permission to publish in the review to be shown when the Project completed.
If you want to put your Project there, you may try to ask the Client to answer the review.

尚、実績公開予定をクライアントが設定した場合には、公開予定日以降に公開されます。