Sources is where you connect the apps that hold people data, so Enterprise Search can sync them into its directory.
Connecting a Source
Pick an app to sync from. The screen separates Connected sources (already syncing) from Available sources you can add. Connecting a source lets the platform pull people records from that app into the directory on a schedule you control.
Mapping Fields and Setting a Sync Schedule
Editing a source walks a short wizard:
Map Fields — choose the Connection in Use and map the source's fields to the people schema, such as which incoming field is the name and which is the email.
Sync Schedule — set Sync Triggers to Manually (you trigger syncs yourself) or Scheduled (a recurring schedule you define).
Saving the source starts a sync straight away, whichever trigger you choose. Manually is the default.
Mapping correctly is what makes the directory accurate; a schedule keeps it current as people change in the source system. You can re-sync a source at any time.