If your HID kit is 35W you don't need to wire to the battery. If it is a 55w HID kit you will.
As far as connecting the HID kit, you need to connect the factory wiring to the headlight assembly. 9006 male plug, connected to the black/ blue plug going into the headlight.
You will now need to cut the grooved circle out of the plastic part that covers where the bulb and wiring are on the headlight. This is where you plug the Spec D headlight H1 connectors to the "wall plug" looking part of the hit kit.
From here, that wall plug part should run to the ballast, then come out as 2 wires that turn into small connectors then connect to the light assembly. Put the wiring through the hard plastic back of the headlight assembly and pull the grommet through so it seals the hole so no moisture can get in. Connect the bulb to the housing and that should be it! Test that the HID bulbs work before installing the bumper. If they don't turn on, you may need to switch wires that connect to the wall plug looking piece. I think black is positive and blue is negative if I remember correctly from when I did mine. Hope this helps. Let me know if there is anything else you need to trouble shoot!