I have not yet been selected but I remember when I applied for different permits and visa, first on the top said it belongs to whom and also there was a ? Mark next to each document requested and explained what should be uploaded. Hope this helpsThey usually require to establish the relationship between the sponsor and the sponsored. So it would make sense for me to upload my own birth certificate as that would show they're indeed my parents. Uploading my parents' birth certificates doesn't really establish anything?