Got my first VEX kit, question about a couple of parts.

[lakedawgs]

HI
Just bought a used VEX V.5 kit and VEX Explorer. Both seem fairly complete.
Introducing my 10yr old to robotics. Need help with a couple of parts.
Please see the attached photo.
1) how do I charge this battery pack. I do not seem to have a charger. Any other options?
2) Is this battery pack used on the robot for power? Wondering why there are 2 battery slots and a gap with 6 more slots.
3) A small turquoise silicone sleeve, a small black gear with metal collar, a small white gear. I have a few of the black and white gears. They just seem very small compared to the other gears in the kits.
4) Small, angled, oddly shaped plastic piece, what is this?
5) Is this just an 'extension cord' for a motor or peripheral?

Sorry, for what are likely stupid questions. I have been reading up a lot but the above stuff has me stumped.
THANKS
Lakedawgs