Assign LED

I need a help!

I'm doing a code that has 4 states, (in verilog).

I would like to know how to assign this states on LEDs...

for exemple:

when the code change to other state, the respective led on light!

i try to describe it:

module { output LED_P[3:0]};

....

assign LED_P = State;

...

endmodule

but it doesnt run....

could you help me?

thank you very much!