What is instructional design? Instructional design is the process by which instruction is improved through the analysis of learning needs and systematic development of learning materials. Instructional designers often use technology and multimedia as tools to enhance instruction. Remember what 4 of our classmate present in the class? That is instructional content or also known as educational program.This link an example of educational program. http://www.learningplanet.com/act/abcorder.asp
In order to build such successful educational program, a framework is crucial to organize and structure the process of creating instructional activities. That framework or guidelines we call as instructional model. The model guides you through the process of creating effective educational courses and materials for your audience. ADDIE model is one of most popular model because of its simplicity and ADDIE model is basically a generic, systematic, step-by-step framework used by instructional designers, developers and trainers to ensure course development and learning does not occur in a haphazard, unstructured way. Following diagram illustrated ADDIE model.

ADDIE is an acronym for Analysis, Design, Development, Implementation, and Evaluation.

(Picture shows the paper-pen activity.)
Suggested Reading of Instructional Design;
www.instructionaldesign.org/models/index.html