Item enchantment question

I must be missing something, but I can't find on either the Core Rulebook nor in the PRD how to add the +1, +2, +3, +4, +5 enchantments, like what spell and CL are required?
I found the list for the special abilities but not for the simple +x enchantments...

Pls, help...

Just bumping, this was a 0 post thread, so I don't think anyone saw it.

Caster Level for Weapons: The caster level of a weapon with a special ability is given in the item description. For an item with only an enhancement bonus and no other abilities, the caster level is three times the enhancement bonus. If an item has both an enhancement bonus and a special ability, the higher of the two caster level requirements must be met.

Creating a magic weapon has a special prerequisite: The creator's caster level must be at least three times the enhancement bonus of the weapon. If an item has both an enhancement bonus and a special ability, the higher of the two caster level requirements must be met. A magic weapon must have at least a +1 enhancement bonus to have any melee or ranged special weapon abilities.

OK, so I did miss something, thank you very much for the assist.