Hi Bee,
Please follow the below steps :
1)Press the Reset button (and keep it pressed) while power the board with the OpenSDA USB connector(J13):.
2) The board will show up as BOOTLOADER drive on your system:
3) Copy"17_OpenSDA_FRDM-KL46Z.bin "(I attached it for you) to the BOOTLOADER driver:
4) The copy operation takes about 2-3 seconds, after finished , unpower the board.
5) Power the board again normally .
BTW, there isn't need connect SWD on your board.
BR
Alice