Unscrew, then pull crown out 2 clicks. Spin crown, advancing hands clockwise. Keep turning until you notice the date changing at the 12 oclock mark. This is midnight. Then set time as needed. Push crown in all the way. Then pull out one click. Turning crown sets day of week and day of month, turning opposite way. Push crown all the way in and slightly depress as you screw it down until it stops.
Since the Renato brand was bought out by another company, service is still done on the Renato's but in my experience it can take 3 to 6 months to return the repaired watch. Patience may be required, and not all parts are available for this discontinued brand. Luckily, some user manuals are still available online. The Worldtimers are particularly hard to set without the instructions.