Road of Sacrifices Bonfire
If you made it to the Road of Sacrifices Bonfire, then you will want to run down the slope in front of you. Run past all the feathered enemies that sprout wings and drop down onto the ledge below. Once you are down, run under the small bridge and then across the big bridge with all the enemies. Keep running and you will find the Halfway Fortress Bonfire.
Halfway Fortress Bonfire
Once you light the Halfway Fortress Bonfire, run down the next slope in front of you. For this part, you are going to want to follow the left wall until you find the next Bonfire. Once you see a building, turn right and you will find the Crucifixion Woods Bonfire. You are now 1 Bonfire away from Farron Keep.
Crucifixion Woods Bonfire
Light that Bonfire and then drop down into the water. Run towards the open hallway in front of you and you will be greeted by 2 really hard Knights. Run past then and climb down the ladder to the left. One of the Knights will drop down and die from the fall, while the other will come down to fight you. Once you get down, you are in Farron Keep.
Farron Keep Bonfire
Light the Bonfire and defeat the Knight and you will be free to explore Farron Keep to your heart’s content. There is an Estus Shard and an Undead Bone Shard in Farron Keep so make sure to explore it to get all the needed Upgrade Materials.