Using BADI BADI_MAT_F_SPEC_SEL

Hi

Based on the material type I want to make certain fields display when using tranction code MM01.

I dont want to do it through config.

SAP note 746875 suggests to use BADI_MAT_F_SPEC_SEL

Can anyone suggest how to make use of method FIELD_SELECTION in the BADI?

Thanks,

Krishna