In a short answer, value theory implies that something is moral if it is good or brings about good, and immoral if it is bad/evil or brings about bad/evil. Whereas normative ethics says that something is moral if it is prescribed and that it is immoral if it is forbidden.
Value theory will typically fall into one of two categories: either Consequentialism or Virtue Ethics. The Consequentialist is concerned with the outcome of the action (so did the action cause more good or evil) whereas the Virtue Ethicist is concerned with whether the action itself is good or bad; or if it stems from/creates good is the soul/character of the actor.
Normative ethics implies that there is some sort of law which governs human actions, and that you must follow it/not break it. This law could be divine or natural. It could also be concerned with justice or duty.