Its an indoor family event, with white ceiling lights and people in colorful dresses, mixture of portraits, emotions and colors & I have nikon d5300 with default lens kit 18-55mm / 55-200mm. I need help with aperture and switching between shooting modes so that i dont miss out on anything. Its my first shoot. Need help.
Basically, as you sound too unsure about these basic things: Do not switch between any mode, and choose a fully automated mode. Choose Program.
If you want to cool down a bit:
Take some sample shots using:
The maximum aperture your lens has (My gess is arround f/4.
And experiment the maximum ISO you see it is "noise free" enough. Probably arround 400-800.
Additionally, look for a TTL flash and use it, but bounce it in your surroundings.
Try to keep it manual. U can also use program auto but try not to use flash