Fallout 4 is a huge game and there are things that you might miss on your first playthrough. The game has companions who assist you during exploration and battle. You can find the first few during the story missions but in case you don’t want to miss any companion, here’s where they are located.
You may have to do certain quests first before they are on board. For example, to get Brotherhood of Steel captain Danse you have to do his missions first. Danse is a huge asset during fights and will singlehandedly win small skirmishes for you.
Here’s a video below courtesy of Gametastik that shows you each companion location. Fallout 4 came out on November 10th and is a huge critical and commercial success, selling well over 1 million copies during the first 24 hours.