CAN-bus for dummies request

[Oskar]

For a guy like me who knows little of a lot of things, I've come to a point where I need a tap on the shoulder or a punch in the face to take the next step in my project. So I am restoring and converting a 1964 VW Beetle, and for this I will be using,

Leaf gen 2 motor and inverter with V3 mainboard and Leaf adapter, now tested and running.
TC charger 3.3kW CAN-bus controlled
Chevy Volt DC-DC converter model MSE716
Hübners BMS, thanks Johu, I've replaced all diodes now
Isabellenhütte IVT-S 1000A that should be on the way pretty soon.

Now I need to know how to get these work together as safe and easy as possible. To be honest I really don't know how, where or when what messages should be on the bus. DC-DC converter seems pretty basic, one message every 100ms to keep it on? Is this something the mainboard could handle when ignition is turned on?

[EV_Builder]

Yes, in a VW beetle that would be the way togo i think.
Draw a sheet with all the wires and connections and don't forget the termination of the bus (120ohms).

What wil be your GUI / screen?