VDSA is a tough one to get in with a PUG. Suggest you get some friends or guildies together that want to spend time learning the mechanics (if they don't know them) and go for it. First timers can expect to spend a long time in Vet DSA. Anywhere from a few hours to a lot more. Saw a group of Streamers once spend over 12 hours in Vet DSA only to give up on the final boss fight. Their DPS was severely lacking but hey, they gave it one heck of a shot!