I got one off ebay too...your's a 1 piece? Pretty basic installation though...
1. Unlatch factory air tubing off intake manifold
2. Unbolt rest of factory airbox/remove any remaining black plastic pieces
3. Jack up car and remove front right wheel
4. Peel away plastic mudguard
5. Remove bottom half of factory airbox/pieces
6. Put bottom part of CAI tubing down through the hole where the airbox was
7. Line up other end of CAI to intake manifold and use silicon connector/metal clamps to fasten to intake manifold
8. Get behind wheel and put air filter on CAI tube...hold with one hand while turning screw on metal clamp thing to tighten securely
9. put mud guard and wheel back in place

I might have skipped stuff but its so easy dude, you can probably figure it out yourself without instructions.