The award is the over-arching qualification. The grade students achieve in each unit contributes to their overall Award grade. As the units contain the information for the exams and when they take place, you need to enter students into both the units (so they are entered for the exams) and the award (so they are entered into the award itself in order to be awarded the qualification).
If students aren't entered into an Award (only units), they won’t get their qualification at the end of the academic year. Sometimes students are entered into units over a number of years, with the award entry coming at the end of their time in school. Please make sure you enter students into the award as well as the units.