I advise against tearing anything apart!
So are saying that you want to get involved with the repair work on the vehicle?
First off, why are you removing the valve cover for? You haven't even tell us what is wrong with the vehicle, just those codes alone? Or because the Chervon station tells you that it needs timing chain replacement.
If you want to do it properly, tell us more about the vehicle.
There are certain diagnostic steps to be done before taking things apart.
The reason for that, those codes alone do not indicate that the engine has any mechanical issues, they simply meant the ECU wasn't seeing the changes in the camshafts' timing, when it commands them to advance. That could be cause by different reason, from low oil level, low oil pressure or some electrical malfunctions.