How to send IMM5476 for accompanying dependent child of 18 years old or older?

[catapv]

Hi there,
My spouse has an accompanying dependent child of 18 years old. I am her sponsor and representative.
The guide is telling :
the following persons would need to submit the online IMM5476e form:

• The principal applicant
• His/her spouse or common-law partner
• Any accompanying dependent child of 18 years old or older

But I can upload only 1 form IMM5476 (for the principal applicant - my spouse). How to upload the form for the accompanying dependent child of 18 years old?

thank you