is this HCM Cloud or on-premise?
For on-premise you have these options:
- Using AD directly - see Adding Support for Active Directory - 11g Release 7 (11.1.7)
- OVD Split Profile - see http://www.ateam-oracle.com/split-profiles-with-ad-and-oid-for-fusion-apps-idm/
- OIF SAML Integration (AD acting as SAML Identity Provider) - see Enabling Oracle Identity Federation - 11g Release 7 (11.1.7)
- Oracle Directory Integration Platform (DIP) - see Oracle&reg; Fusion Middleware Administrator's Guide for Oracle Directory Integration Platform 11g Release 1 (11.1.1)…
- OID Chaining - Configuring Server Chaining - 11g Release 1 (11.1.1)
For HCM Cloud, OIF SAML Integration (AD acting as SAML Identity Provider) is the only option.
Depending on the option you pick and your experience, everything from 1h to several days is possible.