The section Key Concepts When Using Docker with COBOL Applications outlines the different ways in which you can use containers with your COBOL applications and introduces the recommendation of first creating base images for COBOL Server, then using those base images to create additional images that also include your applications.
This section outlines the steps you need to perform when creating these images.
Once you are familiar with the steps described in this section you should look at the Docker demonstrations supplied with COBOL Server. These demonstrations include all the files that are needed to create example images for use with COBOL Server, and the section Docker Demonstrations contains detailed descriptions of the files contained in some of the demonstrations.
After reading this section and Docker Demonstrations you should be able to create your own images for use with your COBOL applications.