Ive written out 14 simple steps for setting up dual VESC using CAN-bus with bldc tool. 
With VESC-tool, its one click of a button during the setup wizard 
Here are the steps I used to program two VESC to communicate through CAN bus. Using the BLDC tool, and two 4.12 hardware VESC.
1.) Choose a master/slave ESC. label accordingly. 2.) Open bldc tool and CONNECT to master ESC. 3.) open app configuration/general tab, and read config. 4.) set controller ID to “0”, save config. 5.) Choose the appropriate tab for your control type(most will use ppm) 6.) Select the box that reads “multiple esc over can” 7.) save config. 8.) Dissconnect Master, and CONNECT slave esc to bldc tool. 9.) open app config/general tab and read config. 10.) rename the controller ID “1” and select “send status over can” box. Dissconnect. 11.) Connect your canbus cable. I recommend the proper connector/jst-ph 2mm 4-pin 12.) Reconnect Master ESC to bldc tool and read config. 13.) on the right side of bldc tool under the dissconnect button, select the slave controller ID (1) and select the CAN Fwd box. Write configuration, and dissconnect. 14.) Reboot both VESCS and test controller, if only one motor spins, check to see that the “app config” settings for one VESC are the same as the other.