According to UbD proponents, traditionally start curriculum planning with activities and textbooks instead of identifying classroom learning goals and planning towards that goal. In backward design, the teacher starts with classroom outcomes and then plans the curriculum, choosing activities and materials that help determine student ability and foster student learning.
The Backward design approach is developed in three stages. Stage 1 starts with educators identifying the desired results of their students by establishing the overall goal of the lessons by using content standards, common core or state standards. In addition, UbD's stage 1 defines "Students will understand that..." and lists essential questions that will guide the learner to understanding. Stage 1 also focuses on identifying "what students will know" and most importantly "what students will be able to do".
Stage 2 focuses on evidence of learning by assessment. Teachers plan performance tasks and evidence of understanding. Performance tasks determine what the students will demonstrate in the unit and what evidence will prove their understanding. This can include self-reflections and self-assessments on learning.
Lastly, stage 3 lists the learning activities that will lead students to your desired results