You can set up a cron to automatically sync LDAP users using the following:

php artisan snipeit:ldap-sync {--location=} {--location_id=} {--summary}

location and location_id are optional.

So for example, if you know the location_id of the location you're trying to add the users to, you could use:

php artisan snipeit:ldap-sync --location_id=1 --summary

Or if you know the name of the location, you could use:

php artisan snipeit:ldap-sync --location=Queens --summary

See the full documentation on LDAP Syncing for more information.