Connect the RS-232 cable to your PC and the meter. Turn on the meter.
The installation process involves "handshaking" between the PC and the meter:
Only if your WS6906 has a USB host port (some versions do). The SD card method is more reliable.
Some versions of the WS-6906 support a direct USB flash drive update:
: Once the progress bar reaches 100%, click "Finish." The finder should restart automatically with the new software.