Just after you dealt with the Vordt in High Wall of Lothric, you will be grabbed by the Flying Gargoyales and transported to the new area of the city called the Undead Settlement. Here you are now going to fight against the hordes of undead and grab all the treasure along with it.
After the Drop, you will first Lit the Bonfire on the right and then start your Journey. Before heading down go left and grab that white orb then while heading down you can skip fighting the Hollows for now. Head back and stand near the group of Pilgrims and you will see one of them will wake up and ask for your help. He is the Yoel of Londer asking to join you and once ou accepts him, he will disappear and you can find him at Firelink Shrine.
He will guide you with the merchant services, hallowing mechanic and other important information. Now head back and Pull the lever to open the gate where the NPC will release few Hollow dogs to hunt you so kill them first then the NPC. Now Lit the next Bonfire to save your progress and replenish your health. Now proceed to the settlements where some Large enemies with basket are waiting for you. Make you way towards another bunch of Hollow Prayers with a Lady leading them to the fire. Kill her before she hugs you tight and drain all your health.
Now move ahead and explore the ahead, head right where a bunch of enemies is waiting for you, take them down and jump down for shortcuts(it will drain a bit of your health), then go up from the other side to open the door(Shortcut if you are dead). Again head back and straight to the end of the Tunnel and you will encounter the old fat lady again so make sure you kill her fast and head down to the new area.
The Second Bonfire
In this new area as you head down, you will find the second Bonfire to save and replenish your health. As you move ahead you will see someone is attacking you with the Bombs and your enemies are becoming the primary target so keep moving do not stand one place. Go directly inside the building and head upstairs and continue moving.
Head Right and open the Giant Door you will be warned the big Cursed Tree is awaiting back. So get ready for it, but first, you need to deal with the Old Fat lady and few others again. Head forward and unlock the shortcut door which will help you travel here faster than the long cut.
Head of the Church and you will find Siegward of Catarina coming up from the elevator. After talking to him he will inform you that the bombs of arrows which were attacked on you first were coming from this tower and the lift only goes down so head down and get ready to fight the Frost Knight and the Fire Demon. Once you Done fighting them, head upstairs and then climb to the another side to get to the Boss Fight.
Greatwood is a Gigantic Tree who is Curse-Rotted and the one you need to finish in Undead Settlement. The Boss is really Huge and can take you down with ease. So before we start with the Boss Fight we should finish off the remaining. Check out our guide to know how we Defeat the Boss Curse-Rotted Greatwood with Ease and without taking a single blow. Once you finish him off you will getting Soul of The Rotted Greatwood, Transposing Kiln and 7000 souls. Thus completing the walkthrough and don’t forget to check out our Dark Souls 3 Wiki Guide to know more about the game.