Very straight forward. These are plug and play units so no splicing or wiring.
The only hard bits are making the 25mm hole in the dust cover and finding a place for hiding the ballasts
Remove dust cover
Remove halogen bulb
Drill 25mm hole in dust cover
Put in HID bulb
Connect HID bulb to ballast
Connect HID bulb wires to stock headlight wires (H4 stock headlight plugs has 3 prong, the HID has two, just find the - and + buy testing)
Then disconnect them as you will need to feed all the wires through the dust cover
The grommet on the HID bulb wires fills the hole in the dust cover so the elements cannot get in
Thats pretty much it.
Will take around 20mins-30mins to install.