The Cairn Stones

This is the third quest in the first act. It is given to you by Akara in the rogue encampment. This quest is were the game really starts to get challenging. It's the longest quest in the first act, and took me about 3 hours to complete. So at first you have to travel to stony field, and then follow the path in stony field to the underground passageway. You'll have to do lots of exploring through the underground passageway to find the exit, but once you do you'l end up in Dark Wood. Explore Dark Wood until you find the "Tree of Unifuss" and once you've found it, pick up the scroll and return to Akara. and by the way, the tree is guarded by a champion gargantuan beast so just be prepared for a fight.
                  Once you've given the scroll to Akara she'll translate it so that you can read the instructions. You then have to go back to Stony Field and touch the "cairn stones" in the order that the scroll tells you. A portal will open to "Tristram" and you can go inside and rescue Deckhard Cain. Before you go into tristram make sure you are atleast level 8 and to fill your inventory with health pots, there are lots of champion monsters that will kill you quite easily. If you want to avoid getting killed and dont feel like killing all the monsters and getting all the loot. Then when you get into Tristram just run to the center, free Deckhard Cain, and run back through the portal. But I suggest just leveling up so that you can fight the monsters.

Tip: When your in Tristram, look around for an object called "wirts leg", this will prove extremely useful later on in the game.