Chapter one: Finding Survivors. You need other people to help you survive. Look at Megaton, a prime example. Start to gather supplies with these survivors as you trek across the wastes. Look for a place to settle down. Old buildings, with a lot of space and a lot of rooms. Underworld is the example here. Ensure this building is in a safe spot where enemies and creatures won't bother you.
Chapter two: Establish teams from these survivors for different needs. Those adept with combat can search old ruins for food, water, guns, and ammunition. They can also bring back objects for the building all of you are living in, such as beds, cabinets, lockers, and chairs. Other teams such as medical and Engineering. All the while searching for more survivors. It would also be wise to get the word out to attract people you can't directly talk to. Example: The Lone Wanderer never meets anyone from Underworld, yet they hear about it and travel there.
Chapter three: Contacting other survivors should be among the first things you do. Like I have stated, band together to survive.
Chapter four: Let nature take it's course. As more and more people find there way to your settlement, it is natural for the men and women to find love. If not, inform the people of the necessity of repopulation.
Chapter five: Most people you find won't be very skilled in the way of architecture and Engineering. So, for the time being, focus on restoring your own building, inside and out. Make sure it stays on a solid foundation and the inside is partially renovated. Rebuilding is more that just your settlement; you need to find other settlements and work together to rebuild.