Protection does four things, and all four only apply in play.
Protection: Protection is a static ability, written "Protection from [quality]." See rule 502.7, "Protection." A permanent or player with protection can't be targeted by spells with the stated quality and can't be targeted by abilities from a source with the stated quality. A permanent or player with protection can't be enchanted by Auras that have the stated quality. Such Auras attached to the permanent or player with protection will be put into their owners' graveyards as a state-based effect. (See rule 420, "State-Based Effects.") A permanent with protection can't be equipped by Equipment that has the stated quality or fortified by Fortifications that have the stated quality. Such Equipment or Fortifications become unattached from that permanent, but remain in play. (See rule 420, "State-Based Effects.") Any damage that would be dealt to a permanent or player with protection from sources having that quality is prevented. Attacking creatures with protection can't be blocked by creatures that have the stated quality.
