You set the WSO100 installation offset using Maretron's DSM200 or DSM250 display in the following way. Enter menu mode, scroll to "Configuration…" and press enter. Scroll to "Device Configuration…" and press enter. Scroll to the row containing the WSO100 and press enter. Scroll to "Installation Offset..." and press enter. Follow the instructions on the screen. Please note that if you are not motoring directly into the wind, you will not get accurate wind direction after you perform the offset. The faster you can motor into the wind and the more directly you are pointed into the wind, the less error you will have. The best possible way to perform the offset is on a perfectly calm day and motoring as fast as possible.