Please don’t connect an LED directly between an I/O pin and ground without a current-limiting resistor - you risk damaging the LED and/or the I/O pin. In any case there is already an on-board LED connected to pin 13.
The resistors shown are not connected correctly. You need to have the three resistors connected in series (you have that part right). One end of this chain need to be connected to ground. The opposite end needs to be connected to your 12V signal. (This means the signal is grounded through your three resistors.) The Arduino’s ground needs to be connected to the 12V ground, too, to complete the circuit.
With the connections described above, you now have two intermediate junctions between the three resistors. The one closest to ground will see one third of the 12V signal. This is the one you want to connect to the Arduino’s input pin. Check the actual voltage here before you plug it in to the input pin since a mistake in the circuit could cause this to be above 5V in which case it would damage the Arduino.