The cable is a Micro USB (Male) to USB (Male) Cable that connects to the DPV and to your Windows PC.
The instructions are here
I used three different cables before I was able to get a connection between the DPV and the PC. Apparently some of those type cables are only suitable for charging -- the one that ended up working was designed for data transfer.
@Manatee Diver I also made the default startup speed "FOUR". ($d4 )
Lastly I made the Migrate Rate 1,000,000. ($m1000000)
I don't mind the speed migration when it's changing the scooter to be slower on startup. But, I really did not like it when it would make the scooter restart at a faster gear than what I was using when I stopped. If I'm creeping along at speed 1 and stop, when I restart I want it to start up still at speed 1.
The custom firmware from Ben Woodill implements that. I.e. it gets rid of speed migration for gears that are lower than your default start speed.
It also adds cruise control, reverse, and a "jump speed" option where hit the right number of trigger taps and it will jump from wherever you are all the way to speed 8.
Highly recommended and should be easy to load up now that you've got the VESC tool working for you.