You will receive this quest in the Enclave. Before you leave, visit all of the merchants and use the stash chests if you need to store any cool loot. Also, speak with the guy who has a curly Q over his head if you want to reset the last three levels of skill allocation. You really only need to do this if you aren't happy with where your character has been going thus far, and since you're early on in the game doing this doesn't have any impact on anything. Now that you have a better idea of where you want to go with your character, you will want to make sure that you aren't wasting any skill points.
When you're ready, head over the bridge to the right to reach the Wellspring Temple zone. In order to get there, you wll have to pass through the Path of the Honored Dead and the Temple Steppes. The Path of the Honored Dead isn't too tough an area, being mostly populated with weak undead creatures. Undead archers will attack you from afar, while basic undead will try to get in close and hit you with melee attacks. You'll want to go for the archers and other ranged combatants first, since they can become quite annoying after pelting you with the umpteenth arrow. After they're gone, feel free to take your time mopping up the weak melee attackers. As always, fill out every corner of the map in search of Chests and Rocks. If you come upon a Locked Chest, backtrack and find large groups of enemies. These groups are the most likely to drop a key for the Chest.
As you advance, watch out for huts, caves, and graves. All of the aboe serve as spawn points for enemies, so wait for them to emerge and farm them as they enter the battlefield.
You will soon reach the Temple Steppes. In this area, you can find plenty of side quests and extra loot. You will want to fill out every corner of your map in this large area, and take on a few side quests before committing yourself fully to the story and its mission. This is a good area in which to farm some gold, loot and experience. Also, be sure to activate the waypoint towards the beginning of the area as you pass by it.
As you explore, you may encounter Fishing Holes. After clearing out all of the nearby enemies, you can use these areas to hunt fish. Hit the left mouse button as soon as the closing ring around the edge of the fishing icon fits perfectly around the circular hook icon. The timing is a bit tricky and may take a few attempts to nail down, but soon you'll be catching fish with the best of them. When you have fish, you can feed them to your pet for buffs and other effects.
Continue exploring the area. You may come across certain areas littered with bear traps. It probably goes without saying, but try your best to avoid these if you can. If you simply have to run over a bear trap, do so quickly. They take a second or two to trigger, giving you just enough time to haul tail out of the way. Similarly, whenever you go underground in this area, watch out for bomb traps. These devious little traps will be hidden inside of certain urns, and will deposit a bomb instead of loot on the ground. You will have a few seconds to back off and seek cover.
As you move about the Steppes, you'll likely encounter an Enchanter. As mentioned in our beginner's guide, you can pay the Enchanter to upgrade your items with Enchantments that add special effects.
When you're ready, head towards you waypoint and across the bridge leading to the temple entrance. Go inside of the temple. You will have to work your way through two mazelike floors all filled with enemies. As always, you will want to fill out your map by exploring every nook and cranny you can see. It's possible to discover Secret Areas here that aren't indicated on your map. Watch out for traps, stay mindful of your surroundings and the enemies within them, and keep a good eye on your health and mana bars, and you should be fine.
Once you make it to the lowest floor, you will find a door leading to the lair of General Grell. Pop as many potions as you need to completely refill your health and mana before entering the lair. Grell will spawn tons of minions for you to fight. Take care of them first, and then focus your attentions on the hulking brute. Grell will occasionally summon new minions into the area. At these points, step away from Grell, backpedal some to lead the minions into a choke point, and take them out one by one until only Grell remains again. Keep a close eye on your health during this battle; Grell's attacks are powerful and you don't want to die unexpectedly.
After the battle, loot the corners of the room for treasure before opening the Boss Chest. Loot everything and speak to the Guardian to end the quest, and then head back to the Enclave through the portal.