Search the Help Documentation files for Create Elements from an external file, this will explain it all.
"PointSplineLoft" is an Excel file that can be downloaded from there and inside it, select Enable Macros. On the front Excel Sheet is some sample data. Select Tools => Macro => Macros, this will open a list of several Macros, select Feuil.Main.
Run that Macro and this appears;
Type in the kind of entities to create (1 for points, 2 for points and splines, 3 for points, spline and loft):
In the already opened CatPart the Points whose coordinates are on the front sheet will be created.
This has all been covered in this Forum, see thread560-39970, Mar12 2003.