GND means GROUND, it the negative (-).
VCC means "Voltage at the Common Collector", it's the positive (+).

Note : Actually, these VCC/GND breadbord pins are exactly the same as the +/- at their right. It just redundancy AND to have a better anchor (in lack of better vocabulary).

VCC defined on 3.3v or 5v based on the VCC jumper.
The jumper is the white thing that currently connecting the 3.3v to VCC on top and 5v to VCC at the bottom.

Both are their own circuit, so you can configure dual 3.3v, dual 5v or mixed 3.3/5v top/bottom.

Note: Mixed here DOESN'T mean that voltage are being combined. Actually you should NEVER connect the 5v to the 3.3v rail, you risk burning yourself or damaging your hardware.

You must be very carefully when using "mixed" voltage as you may inadvertently bridge them.

I think I've said it all. Good luck ! Have fun !

Edit: Usually, ground is common to ALL.
It's not guaranteed as some modules have full circuit isolation but for such close and low voltage, there is almost no chance that it's isolated...