There will be multiple branches/methods on how to get either The Enclave Ending, The Midwestern Brotherhood of Steel Ending, Undead Conquerors ending, Missouri Rangers ending or The Independent Missouri Ending.

For example, one method of getting The Independent Missouri Ending is to have the player kill The Enclave when you first meet them in Jefferson City and not be apart of any of the main factions. When all of the Enclave soldiers are dead and you leave their base, you'll get the ending.

Another method of getting the Independent Missouri Ending is, near the end of the game when The Enclave and BoS are fighting for control of a secret military base that contains the controls for a satellite that can drop an orbital bombardment on any target, the player will have the option to drop the bombs on both The Enclave and BoS wiping them both out leaving Missouri Independent from their control.