The Cannondale Habit Neo / Tesoro Neo range I know fairly well, but the "Nero Trail 3" isn't a model I can place with confidence. Cannondale's eMTB naming has gone through a few iterations, so it's possible this is a regional name or I'm simply not recognising it.
That said, if the bike genuinely has a pre-installed light cable, the most common setup on Shimano-powered Cannondale eMTBs runs an SD300 wire from the motor up through the frame to somewhere near the head tube, either terminating at a rubber bung in the headset cap or tucked behind the stem. Worth pulling the headset cap off first and having a look, as that's the most common exit point.
For lights, if it's a Shimano EP8 or EP801 motor, you'd want something designed for the e-bike port specifically, like the Shimano Di2 compatible lights (the SM-DUE10 junction box is often needed as an intermediary). Alternatively, plenty of riders hardwire third-party lights directly to the motor terminals if they want more output than the OEM options offer.
Could you double-check the exact model name? If you can confirm the motor (should be on a sticker on the motor housing) that'll let me give you much more specific wiring advice. The Shimano E-Tube ecosystem in particular is very well documented here.