If your family members wish to follow you to Canada at a later date, they must complete a separate application for admission.
No, you got this part wrong. It should be:
Each individual can apply separately but can choose to travel on the same date, together or go to Canada on different dates. The first family member who applied and got visa doesn't have to be the first person to travel to Canada. Instead, he/she can choose to do so after the next family member.