AoA bro. Its nice to hear that you have a Cultus. Ma sha Allah. Drive safe.
Well, I cant remember the exact location but I do remember that we had to tear the white clothing under the seat to put the LEDs in. Sorry I cant take the picture as I sold the ride long ago.
You can take the ride to any good car accessory shop and they will help you to put it under the seats 
best of luck 