An Instructional Designer designs the instructional materials,
like an architect designs a building. The Subject Matter Expert (SME) is one who is familiar
with the instructional content, and who provides the building materials
to the architect
to design the building accordingly.
ADDIE Model
The ADDIE model is one of the first instructional
design models, and is
popular because it's simple, easy to use and flexible.
Following this model can help you understand the process
of developing learning content.

During analysis, the designer develops a clear
understanding of the "gaps" between the desired outcomes
or objectives, and the audience's existing knowledge and
skills. The design phase documents specific learning
objectives, assessment instruments, exercises, and
content. The actual creation of learning materials is
completed in the development phase. During
implementation, these materials are delivered or
distributed to the student/learner group. After delivery, the
effectiveness of the learning materials is evaluated and
assessed.
The process is cyclic in nature. Depending on the
situation, the designer may start from any stage of the
ADDIE model and build on previous outcomes, and the five
stages may intertwine with each other.