Step 1: The Tower Key
First off, you’re going to need to unlock the tower area of Firelink Shrine. You can find this area by going up the right staircase as you enter the shrine, then through the arches. The door is currently locked, but there is a way to fix that.
The Shrine Handmaid (old lady in the chair on the way to the blacksmith) sells the tower key for the hefty price of 20,000 souls. But trust us, this is an investment that is worth your time as it unlocks a variety of useful items, including an Estus Shard and the Covetous Silver Serpent Ring.
Once you’ve saved up the souls, unlock the door and ascend the tower. There are a wealth of items available to you now but for what we want, drop down onto the roof of Firelink Shrine from the bridge and go over to the crow’s nest. Yep, just like the other games in the Souls series, there is a crow with an annoying voice that you can trade items with.