help please!!! I'm stuck with commonjs

i have here a 3 issues that i need help with,one is USE STRICT STATEMENT(i don't know what is that) and other TWO are COMBINE PREVIOUS VAR STATEMENT(i don't know what to do here) here is the code I'm using...i would like to learn how to use alloy but there is no simple explanation or guide to it.

// win1.js
function Window(){
  var win1 = Titanium.UI.createWindow({  
    title:'Tab 1',
    backgroundColor:'#fff'
  });
  var tab1 = Titanium.UI.createTab({  
    icon:'KS_nav_views.png',
    title:'Tab 1',
    window:win1
  });
 
  var label1 = Titanium.UI.createLabel({
    color:'#999',
    text:'I am Window 1',
    font:{fontSize:20,fontFamily:'Helvetica Neue'},
    textAlign:'center',
    width:'auto'
  });
 
  win1.add(label1);
 
  return win1;
}
 
module.exports = Window;