how to use GHA (Generalized hebbian algorithm) operator ?

pariB

hi,
i have a .csv file. there is 541 example in file with 40 attributes . some attribute are nominal and i need to convert them to float or decimal numbers.i use "nominal to numeric" operator but it doesn't  map each nominal value to a specific float or decimal number . after a few search i found that after "nominal to numeric" operator  i should use "Generalized hebbian algorithm" operator (GHA) .could any body help me how should i use it ?