The file contents are shown in a series of data columns with headers. The column headers will categorize the data to be imported. Click the header to reveal a menu and set the data type for the column. In the example shown in the screen capture above, the first column contains the Control Point's ID. The ID type was selected using the drop down menu in the column header:
This tells PhotoModeler that the 1st column of data is to be used as the point's ID. The data types need not be in any particular order. Select the type corresponding to the data for each column. If your file contains unimportant or unsupported data columns, select the "Ignore" in the header and that column will not be imported.