An intro on esk8 batteries and notations:
VESC is a Variable (changeable) ESC. Instead of your esc being a mysterious black box that makes your motors turn, you can connect to a vesc with your phone or pc and tweak all sorts of values. Throttle curve, motor amps, brake levels and curves, etc to really let you dial in your own settings to your liking. The downside is that 90% of the vesc settings aren’t meant to be messed with, so you can easily fuck things up when programming it. Lots of tutorials here on how to set them up. You shouldn’t have a problem with a decent engineering background but everyone makes mistakes.