OpenLDAP is not part of Viya 4, though I think the viya4-deployment project can deploy it, so your question isn't specific to SAS. Documentation on how to use ldapadd can be found here:
-- Greg Wootton | Principal Systems Technical Support Engineer
The SAS Users Group for Administrators (SUGA) is open to all SAS administrators and architects who install, update, manage or maintain a SAS deployment.