And you would probably need another dose of melatonin that night, now at 10 PM local, European time. And again, get up in the morning. We also recommend going for a half-hour walk. You don't want to wear sunglasses, because the whole point is to reset the biological clock by letting light fall on the retina. But of course you don't want to stare at the sun, because it will destroy your retina.
Ambient light is fine.
Even on a cloudy day, you're getting more than enough light. Another recommendation is to avoid taking naps at your new destination. Because what you're doing by napping is keeping your clock set to your home time zone. Instead, you should stay up the entire day. Then go to bed at the appropriate time in the new time zone.