N-step BADI workflow

Hi gurus,

I am using the N-step BADI WF WS14000133 in which it is prequesite to implement the BADI BBP_WFL_APPROV_BADI, using this , my requirement is to get the list of approvers for the requestor. please can any one suggest me how to implement this BADI ,or point me to sources where i can get an idea of how to implement the BADI.

Regards

Narendiran Rathinavelu