Generate Random Number in Unity

I wanna create a slender man game in unity. I made these following rules:

[number code] [paper location]
1 Forest
2 Truck
3 Tunnel

How can I make a js script that will randomly choose from 1-3? I tried reading the random.range function but I really don’t get it. Thank you for you help!

var RandomNumber : int;

function Start(){

RandomNumber = Random.Range(1,4);


This will choose a random number between 1 and 3. Hope this helps!