The Fallen Star is the first quest you begin with upon starting a new character in the Diablo 3 Beta, being the sort of introductory quest which serves to help take things easy on you while you are familiarized with the game controls and gain the first few levels. Progression through this quest, like the others, is essentially the same no matter what character class you play ass minus the dialogue that takes place.
You can find a video playthrough of this quest here.
Game start: Make your way to the New Tristram Gate and Kill the Dead attacking the Gate
Upon beginning a new character and starting the game, your first task will be to travel up the small road you start out on to reach New Tristram and talk with Captain Rumford. After a brief conversation you will be assaulted by two separate waves of Risen, the second being much larger than the first. This is a good time to test your abilities and learn the controls, which are easy to pick up, as the Risen are fairly weak and easy to kill.
Talk to Captain Rumford and Leah in the Slaughtered Calf Inn
Once you have beaten back the attacking zombies, talk to the captain to open the gate to New Tristram then head to the Slaughtered Calf Inn to talk to Leah, Deckard Cain’s niece. She will alert you to Deckard having been left behind in the depths of the Old Cathedral, however it is cut short when some of the ill soldiers turn into Risen and attack.
Kill the Risen, Talk to Leah again and Talk to Captain Rumford again.
When the Risen turn, dispatch them with Leah’s help to learn just what foulness plagues New Tristram. Afterwards you can head back outside and over to the gate where you will have to talk to the captain again.
Kill the Wretched Mother
Again, your conversation will be interrupted when a Wretched Mother leading a pack of Risen attack the nearby barrier, destroying it and falling upon the guards. Quickly help with the defense to be given your next task which you can now head towards with the barrier out of your way.
Kill the Wretched Queen in the Old Ruins and 3 Wretched Mothers (Bonus)
Head past the ex-barrier to start making your way through Old Tristram Road to get in the true are exploration and monster slaying portions of the game. At this point you will start finding more drops in a wide variety while encountering a wider array of enemies in the Diablo 3 Beta such as Quill Fiends and the Walking Corpse. Search a bit off the beaten path to find the Wretched Mothers you need to slay for the bonus objective, which aren’t that hard to find given that the area is not that expansive.
Once you reach the Old Ruins you will find the Wretched Queen right by a waypoint portal. Try to focus on damaging the Queen as it can raise additional enemies. It shouldn’t be too hard to drop since it a minor boss in an early part of the game. Mainly it has about twice as much health as the regular variety of mothers.
Use the Old Ruins Waypoint and Talk to Captain Rumford
With the Wretched Queen down you have wrapped up the first quest in the Diablo 3 Beta, The Fallen Star. Just utilize the nearby waypoint in order to teleport yourself back to New Tristram, saving yourself the long walk back and talk to the captain to get your gold and experience reward.