Once you have enabled scheduling in the local instances, the scheduler will run at that specific time and sync(download and import) the metadata from that central instance. There is no other manual intervention required from the users at local instance.
After the scheduler has completed the sync, the local instance will now have the metadata exactly as created at the central system. Note that, passwords of users are not synced. They are nullified for security reasons. After metadata sync, passwords of the synced users need to be reset using Admin user.
Every time a new version is created at central system and synced to the local system, these versions are created as entries in a table that is available for view on the Settings app.
To view the metadata versioning table at the local instance, Go to Settings > Synchronization > Enable Versioning for Metadata Sync.
Enabling or disabling versioning for metadata sync at local instance, will not hinder metadata scheduling / sync process. Because the Metadata Sync Task interacts with versioning end points of the central instance and not of the local instance.