you will need 1-2 pounds of live sand per a gallon, 1.5-2 pounds of live rock, lighting 10,000k and a antic, power filter for mechincal filtering, and a protein skimmer. just my opinion but I wouldn't start out a saltwater tank in anything smaller then a 55g. possible a 29g.
just piece it out. stand, tank, or stand tank and a canopy. them sump with over flow box, then return pump, then protein skimmer and pump for portein skimmer, then a bag of live sand, then live rock, and r/o water and a bag of salt or you can also buy premade saltwater from LFS.
you will also need a test kit and hydro meter..
any questions, just ask... I'm also a new... just piece it out, and take your time... with patience. you don't want to rush a saltwater tank.