Require validation for Bp Advance limit

hi

I'm New For to write SP Validation please Assist me

OCRD.CARDCODE,OCRD.U_APPRWO/PO [ HERE WE ASSIGN SOME LIMIT OF  VALUE] THEN  IN OVPM .NODOCSUM [ HERE WE ASSIGN SOME VALUE TO ISSUE FOUND ]

, IF BP ASSIGN LIMIT VALUE AND OUTGOING ADVANCE VALUE IS GROSSED TO BP LIMIT VALUE THEN SYSTEM HAS TO RAISE ONE VALIDATION

Thanks& Regards

AndakondaRamudu