For example:

1. Click File | Open in Worksheet, select the data file and click Open. It opens in the worksheet.
2. Click Data | Data | Assign XYZ Columns.
3. Select which columns are the X, Y and Z columns and click OK.
4. Click Grids | New Grid | Grid Data.
5. In the Open Data dialog, select the open data file from the list of Open worksheets and click Open. Opening the data file from the list of Open worksheets is the only way for Surfer to recall the column assignments. If you select the data file from the top navigation area and clicked Open, it opens the data file without the assigned columns. 
   
6. The XYZ columns are automatically assigned in the Grid Data dialog to the same columns selected in the worksheet.

Updated November, 2021