How do I include my sister in the family information form?

[bp8492]

The first page of the family information form only contain fields for applicant, spouse/partner if any, mother, and father. No fields for siblings.
However, I have a sister. Although she is currently living with us in our home country, Indonesia, I think that I still have to include her.

The question is, how?

 

[ashnamehta_023]

SOP
mention about her and what is she doing- working/study. Having a sibling back home, strengthens your home-ties