Hello 60010001@kmitl.ac.th,
It seems there are two revisions for the MPC5748G board: reb B and rev D. From the images you have attached I see that you own the rev D.
Anyway, basically the J11 sets the power source and if you try to power the board only for the computer, then you have to set it on the position 2-3. The two LEDs that are turned on, specifies that the voltages 3V3 and 5V are ok.
https://www.nxp.com/docs/en/quick-reference-guide/DEVKIT-MPC5748G-QSG.pdf

Leave it on the position 2-3 if you are only powering the board over the uUSB and try flashing the bootloader on the board. The target seems to be detected now so please, retry a Simulink model over the PC8 and PC8 of the LinFlex2 serial.

Hope this helps,
Marius