To be honest, you dont need to upload the documents. The myCIC system is automated and once the agent processing your file clicks that he has requested some certain things, the system will automatically say you shuld upload it. for example in my case, i was asked for a us fbi pcc but i dint submit it cos i dint stay in the US for upto 6months. i simply uploaded a letter in that spot but the system was prompting me for things like, when is this pcc expiring, when was it issued, i just wrote random dates there and still got my passport back.
i know its not easy bt the truth is once u get ppr, you shuld relax bcos ur application has been approved....
all the best guys!!