After performing one or more of the Companion Subquests, seek out Skjor who can be located within the walls of Jorrvaskr. Skjor will inform you that a scholar has requested the aid of the Companions some time ago to retrieve a fragment of Ysgramor’s Blade. This task will be given to you as a trial to see if you are worthy of joining the Companions and Farkas will be assigned as your Shield-Brother.
Speak with Farkas and follow him out of Jorrvaskr, through Whiterun, and Northwest to Dustman’s Cairn. Once you enter, follow the path through the dungeon heading through the an iron door to fight off a few Draugr, followed by a wooden door, and a second iron door.
Note: As you travel through this dungeon, as you should in all dungeons, make sure to scour every nook and cranny, check every dead body, and search in every chest and container. Even if you ignore all the loot that you will come across, doing this usually nets a large some of Gold to help during your journey through Skyrim.
After passing the second iron doors, head down the stairs and notice the two gates, one of which is closed. To the left is an Arcane Enchanter in case you wanted to add any enchantments to your gear mid-dungeon (some people get their kicks like that i guess.) Enter the gate on the left and throw the lever which will open the other gate but will lock you into the room. Keep an eye on Farkas and witness a very interesting turn of events; Farkas will then open the gate for you. Continue your journey deeper into the dungeon being careful of the pressure plated traps.
Once you reach the next set of wooden doors, head up the log stairs and be sure to investigate the room to the east of the three coffins; inside this room is a Chest with a Master level lock on it. If you are skilled enough to pick this lock you will be rewarded with a Flawless Garnet, 134 Gold, a Silver Amethyst Ring, and a Dwarven Greatsword.
Continue along the way and eventually, you will arrive at the door to Dustman’s Crypt. Once inside you will eventually run into an iron door that requires a key to open. If you followed the above NOTE from earlier you should already have the key, if you do not, search the chest that is located in this same room along the Western wall to obtain the key.
Continue along the path to encounter a few skeevers, and a Giant Frostbite Spider. After passing through an underground cavern you will eventually reach an iron door leading to the main tomb room. SAVE HERE because beyond these iron doors there are about two dozen Draugrs, including a Draugr Wight but along the far West wall awaits a new Word of Power (Fire Breath), a chest, and the elusive Fragment of Ysgramor’s Blade.
Once you have cleared this room and looted everything of value, head up the log stairs to the South and exit the tomb via the hidden passage along the South wall. This passage leads back to the first room of the dungeon; exit and head back to Jorrvaskr in Whiterun and enjoy the events that come ushering you into the Companions and completing the Proving Honor Quest.Skyrim Sidequest - Proving Honor,