LSMW change article master data

Dear All,

As I am new in Retail, i need to know detail steps how to perform LSWM (IDOC method) to change material master (MM42)

providing that needed fields are article code - vendor - purchase organization .. and the field to be changed is tax code located in purchasing view.

Or there is another method to mass change for these materials.

Appreciating your quick response,

Thanks..