This quest begins immediately after Extended Family. After the fight with The Lost Wolf, Eivor visits the dwarves at Ivaldi’s Forge to discuss a way of binding the wolf.
You’ll find Ivaldi’s Forge to the south of the clearing where you fought the wolf, in a cave near the centre of Asgard. When you approach him a cutscene will begin with a few dialogue options. Choose as you wish here, and listen to Ivaldi’s proposal to forge the magical cord of Gleipnir. It doesn’t matter whether you tell Ivaldi that he’ll earn his freedom by forging the cord, or merely receive your gratitude.