FCOM Faction Editing Guide
by Kelcken

***I AM NOT RESPONSIBLE IF YOU BREAK SOMETHING***

[Table of Contents]
I. Tools Needed
Ia. Creation Kit
Ib. FO4E
II. Preparing Plugins
IIa. Vanilla
IIb. Using Other Mod Assets 
III. Loading Plugins in Creation Kit
IIIa. Creating Your Plugin
IIIb. Loading Master Plugins
IV. Editing Faction
IVa. Faction Name
IVb. Forces List
IVc. Requirements (have not figured out how to change yet)
IVd. Quest Notifications
IVe. Levelled Lists
IVf. Outfits
IVg. Actor
IVh. Finishing Up in Creation Kit
V. Finalize Plugins
Va. FO4E

[Section I. - Tools Needed]
Ia. Creation Kit - https://www.creationkit.com/fallout4/index.php?title=Creation_Kit
-You have to edit the CreationKit.ini in order to load multiple master files.
-Open the .ini and add this under the [General]
bAllowMultipleMasterLoads=1

Ib. FO4E - https://www.nexusmods.com/fallout4/mods/2737/
-Create a shortcut for the .exe, right click and select Properties.
-Add the following in the "Target" box after the text that is already there
-AllowMasterFilesEdit -IKnowWhatImDoing

[Section II. - Preparing Plugins]
IIa. Vanilla - If you are only using Vanilla files, you can skip this section.

IIb. Using Other Mod Assets - Check permissions for mods that you want to use in your plugin, ESPECIALLY if it is for public release.
-Open FO4E using the shortcut you made and load the mods that you want to use in your plugins if they are NOT ESMs
-Click the file header for each mod, then double click the space next to "Record Flags" and check the ESM box 
-Do this for all mods you want to use, then close and save plugins
-Manually change the .esp files to .esm files in your Fallout "Data" folder

[Section III. - Loading Plugins in Creation Kit]
IIIa. Creating Your Plugin 
-Open Creation Kit
-Click File and Save, then enter whatever name you want for your plugin, then click Save.

IIIb. Loading Master Plugins - Click File and Date 
-Check all ESM files from the previous step
-Check the plugin that you created, and click "Set as active file"
-Click Ok

[Section IV. - Editing Faction]
IVa. Faction Name
-In the Object Window, click the very top "Actor" and then in the search box type "ICOM_Msg_Settings_Factions", then double click the result 
-Choose which Faction you wish to Overwrite, and then replace the name with yours

IVb. Forces List
-In the search box type "forces", then double click the faction list for the faction chosen in the previous step
-Write down the names of the original forces in the order they appear
-Change the names to whatever you want your forces to be called
-Click OK

IVc. Requirements (have not figured out how to change yet)
-Requirements are changed in the Forces list, but I have not gotten it working correctly yet. The changes work, but the forces don't all appear in game if you are playing on balanced mode. I recommend leaving these as they are, and just turning balanced mode off in game.

IVd. Quest Notifications
-In the search box type "ICOM_Quest_", then find the entry for each of the forces that you wrote down in IVb. 
-In Quest Stages, change the Log to whatever you want the notification to say when you start the quest (when you click to the next step, you'll get an error, but I've never had an issue with ignoring it.)
-In Quest Objectives, change the Display Text to whatever you want (originally the same as the quest stages)
-In Quest Aliases, check the Fill Type column and and write down what actor is used for this force (needed for a later step)

IVe. Levelled Lists - You can choose to create levelled lists to give individual Actors within a single force random outfits, or you can just assign specific gear to outfits
-I generally create sepereate levelled lists for Helmets, Torso, Arms, Legs, and any accessories. This way units may appear fully armed up, or with random pieces of gear. I think it helps keep the game fun.
-I do the same for weapons, for the same reasons.

-I'm only going to teach how to do a basic levelled list, but you can do something like IndividualGearPiecesLL->FullArmorSetLL->MasterArmorSetLL->Outift, then each unit with that outfit has a chance to spawn with a random selection of any number of gear sets you've put together
-In the Object Window, expand Items and click LevelledItem
-Right click and click new
-Enter a unique name (I usually do factionname_unitname_type ex. UNSC_ODST_Helmets)
-Right click in the table and click new, then repeat for however many items you have in this category
-In the filter type in part of the name of the item to narrow the list.
-Once done, click OK and repeat for any other pieces.

IVf. Outfits - Create a new outfit for your units, or you can use vanilla outfits
-In the Object Window, expand Items and click Outfits
-Right click anc click new
-Name your outfit
-In the object window, expand items 
-If you used created levelled lists or are using vanilla ones, click Levelled Items
-Search for the lists you want to use
-Drag the lists into the outfit, and click OK
-If you just want to use individual armor pieces, expand armor
-Search for the items you want in the outfit
-Drag the items into the outfit, and click OK

IVg. Actor - Customize the FCOM NPC's to your liking
-In the Object Window, expand Actors and click actors
-Using the list of forces youve written down, search for an actor using what you wrote down in IVd.
-Double click to open
-Change the Name field to whatever you want this actor to be called in game
-Click Inventory
-Select the outfit you created or a vanilla one that you want your unit to use
-In the inventory table, you can click the items already there, then use the dropdown box underneath to select your levelled weapon list, a vanilla levelled weapon list, or individual weapons
-Click OK

IVh. Finishing Up in Creation Kit - Save plugin and Push to PC
-Click File, then click Save and Push Plugin to PC
-I highly recommend testing this in game at this point to make sure everything is working before finalizing.
-If everything is correct, move to the next step

[Section V. - Finalize Plugins]
Va. FO4E - Load You Plugin and change masters
-Open FO4E using the shortcut
-Load the plugin that you made (it will automatically load all of the masters)
-Undo the ESM flag change that you made in IIb.
-In the file header for YOUR plugin, double click on each mod that you changed to an ESM, and change it to an ESP
-Exit and save all plugins
-Go back to your Fallout Data folder and switch each of the plugins that you made ESMs back to ESPs

That's it! This is the method that I use to customize my own FCOM factions!
Huge thanks to:
ElminsterAU for developing FO4E, and helping me figure out how to do some things
MadGodSheogorath for creating FCOM, and for teaching me a little bit about how it works!