Badi issue

Hi guru's

I am new to the BADI and was going through this wonderful blog

How to Implement a BADI in SAP ABAP with Tutorial « SAP Ignite

But i have few doubts

1)when I was trying to enter the data directly in MM01. in the material box which data should I feed..?

2)Moreover if any1 has gone through the link can you clerify where i need to enter the break-point int the class CL_EXITHANDLER’s GET_INSTANCE method. (I have entered randomly )

3)In the statement   if WMARA-MATKL eq ‘A05′ and WMARA-SPART eq ‘02′.

if i enter this  condition than how the program will come to know about MATKL and SPART varibales

please clarify the doubts....!

Thanks in advance!!