Firelink Shrine is the first hub of the game, linking to several different areas. We’ll tell you where to head first in a moment, but first let’s do some exploring…
Immediately turn right and loot the corpse hanging at the edge of the well for three Humanity. Consume at least two of your stocked Humanity and light the bonfire. You can (and should) kindle the fire at the cost of one Humanity. This ups the Estus Flask refill count from 5 to 10 whenever you visit this bonfire. You should also consider using another Humanity to reverse your hollowing. Remember that increasing your humanity count (consumed, not stocked) boosts your item discovery rate as well as curse resistance and other defenses.
You can speak tothe armored NPC nearby to learn of your next objective. Talk to him repeatedly to learn more.
From the bonfire, head up the rightmost stairs and continue up, sticking to the right. Proceed along the short passage until you reach a corpse at a dead end. Loot it for 6 Firebombs.
Go back to the bonfire and head up the stairs again, this time maintaining a more centered direction. Speak to the NPC on your left, Petrus of Thorolund, repeatedly until he asks you to join his covenant, The Way of the White. If you say yes, he will sell you Miracles. There is no drawback to joining this covenant right now.
Pass Petrus and continue up the stairs. Enter the dark room on your right to find two dark doorways. These are actually elevator shafts, though you cannot yet use them. You can, however, walk through either one to safely drop into an area containing several treasure chests. The most important loot here is a Talisman, which allows usage of Miracles (once you have them).
Be careful when dropping off the ledge behind the final chest. Land and immediately sprint left back to the bonfire. You shouldn’t engage the Skeleton Warriors in the graveyard at this point.
From the bonfire, look for some descending steps along the edge of the cliff. Take these to an elevator, which will bring you to the New Londo Ruins. Upon entering this dark area, head to your right and look for some steps leading down.
Where the stairs end, you’ll find a Blacksmith, Rickert of Vinheim, who has a Sorcerer’s Catalyst (which allows casting) and a couple spells for sale. This is a great opportunity to get started down the path of the Sorcerer if you wish.
Note that the undead here are weak and will not attack unless attacked. DO NOT proceed beyond the wooden bridge an into the ruins themselves. You’ll be attacked by ghosts that you cannot yet kill. Return to the bonfire.