This guide is designed to introduce you to systems modeling. The guide presents a lightweight modeling language that builds upon standard concepts within systems theory; such as efficiency, energy and entropy, integration, emergence, functions, environments, etc. What is presented here is primarily qualitative in nature, designed to provide a generic language for structuring our reasoning about systems of all kind. The primary aim of systems modeling is to be able to shift our thinking from that of seeing just parts to seeing whole systems and to be able to communicate this insight. During this guide, readers will learn the language of systems theory and learn how to graphically represent systems. These diagrams and vocabulary will enable us to reason about a wide variety of phenomena while being able to effectively communicate this to others.