At level 35, you can now venture over to the Rikti War Zone (RWZ) and start doing missions that, back in the day, were considered endgame material (not anymore, though). These missions are for levels 35-50, and will supply you with many repeatable missions and lots of XP. "Welcome to Vanguard" is a story arc that you will only get by entering the RWZ.
There are 4 ways to get into the RWZ: portals from Vanguard bases in Atlas Park, Founders Falls, or Peregrine Island, or traveling through Crey's Folly. Once in the RWZ, you'll get a new contact - Levantera. She gives you the run-down on what's going on and sends you on a 6 mission story arc.
You'll also meet the other members of the Vanguard - Borea, Serpent Drummer, Gaussian, Dark Watcher, and Lady Grey. Each will later give you missions as well, as you level up.
This story arc will give you several RWZ badges for your trouble and 15 Reward Merits!
Mission 1: hunt 10 Rikti
Mission 2: bunker raid and save 2 "heroes"
Mission 3: rescue Longbow soldiers
Mission 4: stop Rikti assault group
Mission 5: Rogue Isles industrial park
Mission 6: stop assault on the Vanguard Base
