From your 'My Hub' page (please see below)
On the left hand side of your account, you will see the side menu in which you can select 'Contacts'.
If you click on the client profile
You can then select 'Assignments' from the list below the client profile picture
Click 'Files' which will show all 'Assigned Files' as well as 'Uploaded Files'.
Simply select 'Uploaded' from the top of the page to view any uploaded files from that specific client.