During any move, the first time a model comes into contact with an area of the Battlefield, terrain element, or named effect it is considered to Enter that area, terrain, or effect.
If an effect is over multiple areas or terrain elements (e.g. Void Rifts) the model only Enters the effect the first time it contacts the effect.
If a model is Placed into an area of the Battlefield, terrain element, or named effect it is considered to Enter that area, terrain or effect.