If you are placing a direct composite veneer on mostly ENAMEL, you would etch the tooth with phosphoric acid, place a thin layer of Porcelain Bonding Resin (in place of All Bond Universal), light cure, add composite, polish and finish.
If you are placing a direct composite veneer on mostly DENTIN, you would etch the tooth with phosphoric acid, apply All-Bond Universal®*, light cure, add composite and polish and finish.
* You may place Porcelain Bonding Resin on top of the All-Bond Universal in this case, but it is unnecessary.