A container is an image that includes everything needed to run one or more pieces of software: the code itself, an operating system environment and its associated tools and libraries, and other desired customizations. Containers are “stand-alone”, enabling workflows to be easily packaged and shared across platforms. This hands-on tutorial will provide an introduction to containers, the basics of running Docker and Singularity containers on RMACC Summit, and examples of building Singularity containers from recipe files.