If you haven’t already seen the many Destiny PvP gameplay videos, you can check those out here. However the video below from DattoDoesDestiny explains the mechanics of The Crucible (at the time of the Alpha). The video describes in great detail the maps that were available during the Alpha as well as the Control gametype.
There’s likely to be more PvP maps and gametypes in the July 17th Beta, so be sure to keep following our updates for more juicy info!