Creating BAdI implementation for BAdI BADI_REBD_BUILDING of enhancement spot BADI_RE_BD_BU

Dear All,

We want to put a custom check in Real Estate Transaction REBDBU . We have already used BDT route to create custom fields in General Tab but also want to put validation in data enter in these custom filed . In SPRO we found one Implement Enhancement BAdi for building but we do not know how to use it for our custom check(validation ). Please help.

-Pk