Open your file in Microsoft office excel click save as/save a copy name your excel file click on the dropdown arrow and select CSV (MS-DOS) (*.csv) or you might have to use CSV (Comma delimited) (*.csv) and it should work.

If you are using Google Docs sheets you will want to click on File choose Download and then choose Comma-Separated values (.csv current sheet) and then load the file to the dialer from your PC. If you do not know where you saved the file you might check your downloads file.