Convert the XLS file to the GPX format and the Lowrance unit will be able to import it. You may lose some of the the information from the file but the coordinates and waypoint names should be good. You can easily convert it using the GPS Visualizer website. On the Home page there is a button labeled "Get Started Now!" where you choose your input file and the type of output file format you want. Choose the XLS file you downloaded from the OK site as the input file and then choose GPX as the output file format. After it converts the file it gives you the option to download it. Save the file to an SD card, put it in your HDS, press Pages button and go to files, select the GPX file on you SD card and and it will give you an import option. Import it into the HDS and you should be good to go. Be sure to export your existing waypoints on the HDS to the SD card prior to doing any importing just in case!