After clicking this button you can select multiple pupils by clicking their tiles. They will then turn blue.
To award these pupil click the 'Choose award' button in the top right hand corner of the screen. To award a behaviour to all pupils, click on the "toggle all" button to select all pupils.
You then select a behaviour like you would do for a single pupil by clicking a behaviour tile. You will then get a new sidebar acknowledging the points being awarded. You also have the opportunity to add a note to the points.