Leaders and Followers
You can do your business here as usual like making best friends out of some villagers. If you're ready, head to the second floor and talk to Walter and Samuel. Go back to the Sanctum when you're ready. Check the map. You should be able to see the villagers in need. Help them to gain followers. Check out the Sidequests Section of this guide for details on how to complete these quests.
After collecting enough followers, you can immediately talk to Samuel to start the story mission or just continue doing the sidequests. After signing your contract, the next story event takes place in Mistpeak Dwellers Camp. After the scene, you'll be taken to the Road to Rule.
Road to Rule
There is a new spell available for purchase, as well as some packs and other upgrades. If you're saving your Guild Seals, you should have a lot by now so you may want to purchase additional expression packs and the Ice Storm spell as well. The Pie Maker and Lute upgrades can be left for now since you won't possibly be making a living out of them. Exit the portal when you're done.
After signing the contract with Sabine and the dwellers, his compound's gate will be open. Go inside to grab the Silver Key as well as finding a dig spot. Head to the next objective when ready.