Forget about the 0 volt wire and the 12 volt wire as its confusing you what they mean by this is the wires that go to A,B,C from your power source that you are using to power your points. As for connecting D and E to the bus wire or rail it makes no difference as its one of the same. The only thing you need to watch out for is that you connect D and E to the correct Bus wires otherwise you will short the system out. BTW what are you using to power your points