Actually very simple justbuggin. When you purchase the Dc powered CDI try to ge the pin layout so it'll be easier to wire. It's the same as the AC one except the power source will come from the battery. You will still have the following wire layout;
Green = ground Black/yellow = feed to coil pick up coil wire from stator (usually red/white) to CDI
Then instead of the black/red from the stator you will replace this with a 12Vdc wire from the igntion (usually black)
Now some Dc powered CDI's are 4-pin so you will not have the black/white engine kill wire but some do use this function for the emergency kill switch and if this is the case it wsill be a 5-pin CDI.