“Write the total number of family members included in your application. This includes yourself, the principal applicant, and any family members, whether they will travel with you to Canada or not.
Note: Do not include the sponsor or family members that are already permanent residents or Canadian citizens. Individuals that will not be included in the undertaking should not be included in this total.”
And here is the link which gives detailed instructions for how to complete the questions on each form.
You’ll have to scroll way down to come to instructions for each of the different forms.
That is the complete detailed Guide, and it should be your primary source for clarification on the meaning or wording of the questions.