All of it. If it exceeds limits you have some corrections to do, and you those should also be on your 5500 for the appropriate year.
You are scratching the surface of issues of SDBA only plans... You need more information to determine contribution sources, like a ledger or payroll report.
The brokerage account isn't going to track it by source because that is not what it is designed to do. You need to do source level accounting of contributions, distributions, fees, earnings, etc. outside of the brokerage account.
Do you have software that will do this for you? If not, are you an employee of the plan sponsor or advisor trying to do this without a TPA? If so, you need the assistance of a professional.