If you have some, offer her but if you don’t, find her the chems she needs. When you speak with her, she asks for some Jet. However, to keep them flowing you need to get her some chems and she needs 8 hours of sleep between each intake. Mama Murphy claims she sees visions of the future. Also, build a water purifier, and feed them. Access your workshop and make new beds, furniture inside new or pre-built structures.
When Preston Garvey comes to the Sanctuary, they want you to build the Sanctuary.
Also, agree to join the Minutemen at the Sanctuary. If there are remaining Raiders, clear them out and meet with Preston for a reward. You will need Fusion Cores to run it but if you don’t have any, detach its Minigun. On the roof of the museum, you will find an empty T-45 Power Armor. Loot everything in sight, you can pick up Fusion Cores, Vault-Tec Bobblehead, and a classic issue of RobCo FUN! inside the museum. Use the bobby pin or hack the terminal to open the security gate. Once you are done, drop to the ground floor and reach the basement.
