Hello there!
I see you're taking the big leap and transitioning from the Boeing 737 to the Boeing 747. I understand how the virtual cockpit can be a bit more complicated in the larger aircraft, so I'll do my best to help you locate those important switches.
Seat Belt Light Switch
To find the Seat Belt Light switch in the 747's virtual cockpit, you'll want to look at the overhead panel, specifically on the right side. You should see a panel labeled "Cabin Utility" and the Seat Belt switch can be found there.
No Smoking Light Switch
Similar to the Seat Belt switch, the No Smoking Light switch is also located on the overhead panel. Look for the same "Cabin Utility" panel where you found the Seat Belt switch. The No Smoking switch should be just to the left of it.
Battery On/Off Switch
For the Battery On/Off switch, you'll want to focus your attention on the lower portion of the overhead panel. You should see a group of switches and knobs arranged in a rectangular pattern. This area is known as the "Electrical Panel." The Battery switch can be found on the upper left corner of this panel.
Now, to address the possibility that these switches may not be present in the virtual cockpit of the 747, it's important to note that the default FSX 747 has a less detailed and functional virtual cockpit compared to some third-party add-ons. In some cases, you might not find all the switches you're looking for, or they might not be functional. If that's the case, consider looking into third-party 747 add-ons that provide a more realistic and detailed virtual cockpit. Some popular options include the PMDG 747-400 and iFly 747-400.
I hope this helps you locate the switches you need to get started with your dark and cold 747 flight. Enjoy the skies with this majestic aircraft, and don't hesitate to ask if you need any more assistance!