Unfortunately I cannot tell you how to paint Uruk-hai scouts because I have never collected before.
What you will need:
Blood red (Optional.)
Snakebite leather/buebonic brown.
Big undercoating brush.
1.) undercoat the whole Uruk chaos black.
2.) Drybrush the shield, helmet and armour chainmail
3.) Paint the sword or TIP of pike chainmail and the chainmail armour.
4.) Paint the Faces and hands Scab red.
5.) Paint the trousers either buebonic brown or snakebite leather.
6.) If you want, Drybrush the tip of pikes and tip of the hand weapons blood red.