I have few questions left, and hoping you will not be irritated.

Is there any option in Express Entry to upload supporting documents after submit payment?
If there is any technical problem of transaction during payment submit , can I return to previous supporting document upload screen?(sometime credit card provider bank lock foreign transaction for security purpose)
Is there any option of delete any uploaded document what i had upload wrongly?
Can I upload new supporting documents after submit payment what i had missed?
Please share your valuable experience who already submit express entry application.