Sanctuary Main Story, Minutmen Quest
This quest will be triggered or can be aquired when you complete When Freedom Calls quest.
Related points of interest
Stages of "Sanctuary" quest
1. Talk to Sturges
2. Build sheltered beds for Sanctuary settlers
I've agreed to help the people in Sanctuary establish a permanent settlement.
You have to build 5 beds.
3. Talk to Sturges
4. Provide clean water for Sanctuary settlers
2 water pumps will be enough.
5. Talk to Sturges
6. Provide food for Sanctuary settlers
Harverst and plant some plants. You will find melons and gourd plant behind the workshop house. You can also find many tato plants at the Abernathy farm, southwest of the Red Rocket Truck Stop.
7. Talk to Sturges
8. Build defenses for Sanctuary
Build 3 guard posts or towers next to each other and assign a person to one of them, it should be enough.
9. Talk to Sturges
10. Quest completed
Sanctuary is well on its way to becoming a thriving settlement.