Installing mariadb cluster

Hello everybody. I’m short of time and have no experience with docker that’s the reason I ask you guys to help me with the problem:
Yesterday I was asked to configure MariaDB three nodes cluster across three different docker container. I’ve spent some time to make a research in that matter and stumbled on the following project . I’ve followed the steps but got an unexpected result as I got all three nodes inside one container instead getting them distributed separately across three different containers. The task I got is very urgent! Is there any step-by-step tutorial or article on this matter?