I don't understand what you are trying exactly.
For a first test run you do not need Gimbal or TxPID. What gimbal hardware do you use ?
Seems you try to setup a OPLink not available with a CC3D hardware.
The serial COM3 is not needed for normal setup.
The Setup wizard will help you to configure the board according to your hardware (Rc receiver, Esc...), you should start here, followed by the Transmitter wizard.