What board are you using? If you are using the S32K146 evaluation board, please note that the UART instance connected to the microUSB is actually LPUART1. If you are using an external serial converter, please check the schematic for the board to see that it is actually connected to LPUART0 (the instance you configured in the model).
You might want to check included examples in the toolbox to see how to configure and use different peripherals.