Think of this as describing the purpose of the position, and its role within your company or organization as a whole. A job summary will briefly acknowledge the fundamentals of the position, so leave space on your job description template to answer.
Highlight the day-to-day activities of the position. This will help candidates understand the work environment and the activities they will be exposed to on a daily basis. This level of detail will help the candidate determine if the role and company are a right fit, helping you attract the best candidates for your position.