First I should mention this guide will be using a windows computer as its example
Alot of guides say you need alot of important things to do this but they never mention the easiest way with the little amount of objects
all you need is

The Paint tool from a windows computer (Found In)
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Accessories

Then Finally
VTF Edit[nemesis.thewavelength.net]

Now Open The Painting tool. Make sure you set the size to 1024x1024 for you warpaint
then Work Away while remembering this things:

TF2 Has a specific artstyle:
Their are specific artstyles that are in team fortress 2 if you want your item in it is best to focus on that art style.
The Warpaint ends Matter:
as in its applied to weapons so make sure the ends are made in a way so that it does not seem like some random unfitting texture change line on the warpaint middle

• now Open up VTF Edit Click File>Import.
  
• Find Your warpaint png(s) and put it(them) in
  
• All the default settings should be fine so just click Ok
  
• Click Files>saveas
  
• name your picture and you now how your warpaint as a basic vtf i recommend putting it in a custom folder in documents now to keep track of.

now get to this file locaton
C:\Program Files\Steam\steamapps\common\Team Fortress 2\tf\custom
if their is no custom create one with the exact name "custom"
Create a folder named anything inside the custom folder.
In this folder, create a "materials" folder, and then a "patterns" folder inside of that. The final file path should be:
(C:\Program Files\Steam\steamapps\common\Team Fortress 2\tf\custom\folder\materials\patterns)
Now since this is a basic guide from now on im going to show you what i would do. We will make your warpaint into a civic duty replacement in game so go back to your warpaints folder and:
Make 5 copies of the Warpaints vtf(s)
Rename each one to one of these accept for the original. (Advanced only tip: Also remember when making warpaints each section reskined matters so at the end of these remember which vtf is replacing which. Then you can re arrange the vtfs so they are in the right space for it to look nice):

For Blu warpaint Models:
solid_blu_muted
solid_yellow
For Red warpaint Models:
solid_red_muted
solid_yellow_warm
For Both warpaint Models:
solid_grey
(FOR RECORD I MUST MENTION THAT SOLID GREY MUST CONNECT TO BOTH TEAM COLORS SO MAKE SURE THAT IF YOUR MAKING BASIC WARPAINT SOLID GREY IS ONE THAT SHOULD BE TEAM NEUTRAL)

Now You Have all your Patterns
So Copy All Of Them accept the original vtf(s)
and paste them in
(C:\Program Files\Steam\steamapps\common\Team Fortress 2\tf\custom\folder\materials\patterns)
If this is your second time doing this replace the files in their make sure the old ones do not stay and are replaced with your new skin (If you want to save your old ones for later work thats recommended to cut and paste them)
Now Load up tf2 goto Items then to warpaints find Civic Duty Mk.II (Works For Normal and Mk.II both are connected) and See if it worked. Now if it worked its time to upload them to the game.

Now what you must do is get all the vtfs into the Folder where you store all work in progress content
what i recommend for organization is create another folder in that and put all reskin vtfs for the civic duty in their and leaving the Paint tool textures and original .vtfs outside of that folder so basicaly
All your civic duty reskins are in
\customwarpaint\customwarpaintcdreskin\ (any folder name works)
and all your normal pngs and vtfs are in \customwarpaints\
So now get out of custom warpaints and compress the folder with everything in it.
Now From now on i recommend using the sfm part of this guide before continuing this so you can get the photos and the pictures. I will continue but remember you will need a Thumbnail for your item that CANNOT BE CHANGED LATER. So once all thats outta the way lets continue.
Go into Team fortress 2 click the Wrench icon that takes you to the workshop. Then click Publish New Item Set your Thumbnail Down in the Preview Image section Must be size 512x512.
Then Click Other and find your zip and select it. Tags will appear select warpaint. Then Add your Title and description for the warpaint and click submit and you are done with uploading your warpaint to the Workshop. It is now in the workshop to be browsed.

Credits
For This Part Of the guide it would help for you to Like this guide so others can see it and use it to help them make warpaints.
This Guide was created by me If you want to know how i learned I learned from this guide which can also be used for some information that i may have missed or for a slightly more advanced guide:
Making Custom Warpaints
Thank you for looking at my guide and if you want to show many any of the warpaints you made comment links to them below I hope to see all you in game
Bye...



Bonus: Uploading Warpaints to SFM

So now that you learned how to make Warpaints Lets Learn how to use them in sfm.
You Will need:
SFM duh.
Also subscribe to
Decorated Weapons so you can use these in Source Film Maker.

So First You Must navigate to
<steamapps>\common\Team Fortress 2\tf\custom\
Zip your mod folder aka \custom\Modfolder\materials\patterns while the civic duty reskins still in patterns

goto http://weapons.tf and to the settings button on the website page
Click choose file snd select your modfolder zipped then OK.
Now Do not refresh the page. Pick what weapon you want to get into sfm and then scroll to the Civic duty Option then bam it should appear on the weapon of your choice and scroll back to settings and click save Texture VTF. Do this for all weapons you want reskined in sfm.
Create a new session in SFM.
while its downloading the Decorated weapons navigate to
<steamapps>\common\SourceFilmmaker\game\workshop\materials\models\decorated\
Open the desired weapon folder you intend to include in your scene
go to one of your new weapon.tf vtfs that is the same weapon that you desired in the last step. their should be 2 file sin the decorated weapon of your choice called c_(weapon)_decorated10
take your vtf for that weapon known as just c_(weapon) and rename it to c_(weapon)_decorated10 and put it in the folder. Make sure it REPLACES the one with the same name not just adds both (Remember theirs a vpk and vtf for each make sure it replaces the VTF dont delete vpk)
Now Back in sfm open the console and type:
mat_reloadallmaterials
Now Open The create new model in sfm search c_(weapon)_decorated.
Select and import it.
Now Goto it and switch its skin to skin 18.
Now your skin is in sfm!
Hopefully this guide helped you.
I have made afew warpaints heres one of them that has 2 photos on it for recommended layout for photos to get you noticed in the workshop. The Example Warpaint is Here

The way i learned how to add warpaints to sfm was from this guide

I hope this guide helps you and you make successful warpaints remember
comment any cool ones below and please give this guide a thumbs up so more new warpaint makers create warpaints and upload them so we can keep the community strong. I hope you enjoyed and il see you in game Bye!!!!