Shipping exit - how to create an enhancement spot ?

Hi Gurus,

I need to create an enhancement spot for an enhancement component EXIT_SAPLV56U_002 foe use in Shipping frieght determination.

I need to create a BADI by making use of corresponding method/parameters for internal table I_XVTTK.

Practically what is the sequence of approach do i need to do?

Thanks

Dany