Enchantment — Aura
Enchant creature
When this Aura enters, create a 2/2 white Knight creature token with vigilance. (Attacking doesn't cause it to tap.)
Enchanted creature gets +2/+2 and has vigilance.
You need a creature for Knightly Valor to target as you cast it. There's no way to have it enter the battlefield attached to the Knight token it'll create.