Download SteamCMD from this link:
https://steamcdn-a.akamaihd.net/client/installer/steamcmd.zip

Create a new folder in your file browser to house SteamCMD and extract the contents from the .zip to your new folder. Install SteamCMD to your PC.

1. Open your File Explorer and create a new folder (wherever you want to store your modding files). This folder will contain the assets needed to upload your mod to Steam.

2. Inside your new folder, create another folder labeled "Paks" (without quotation marks). Place the .pak file of your mod inside this Paks folder.

3. Right click and create a new .txt document. Create a name (I like to give it the same name as my .pak file). And most importantly, change the file extension from .txt to .vdf.

Inside the .vdf text file, paste this script:

"workshopitem"
{
"appid" "2254890"
"published" ""
"contentfolder" "D:\mods\paks"
"previewfile" "D:\mods\icon.jpg"
"visibility" "0"
"title" "A Dress"
"description" "A very beautiful floral dress"
"changenote" "Version 1.0"
}
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Notes:
A. "contentfolder" "D:\mods\paks" <- This is the file path to your Paks folder. It should be written exactly as you see here. For example, "C:\Modding\TheKillingAntidote\Steam Workshop\Paks"

B. "previewfile" "D:\mods\icon.jpg" <- This is the file path to your thumbnail image. It should also be written exactly as noted above.

C. "appid" "2254890" <- This is an identifier for The Killing Antidote. This tells Steam what game you are uploading for.

D. "published" "" <- LEAVE THIS FIELD BLANK. A numeric string will be automatically generated once you begin uploading the mod. This is a unique identifier that points to your mod in the TKA Workshop. This is also how you will post updates to your mod over time, by pointing to this Published ID.
__________________________________________________________

4. Create a square thumbnail image for your Workshop icon. It can be .jpg or .png.
Recommended sizes are 128x128 or 256x256, but larger resolutions are supported. Just make sure it is a square image, and that the image file is less than 2 MB.
Name this image whatever you like.

The contents of your folder should now look like this.

1. Navigate to your SteamCMD directory (the folder where you are storing the program).

2. Right click in the empty space inside the SteamCMD folder and select "Open in Terminal". This will launch the Command Prompt.



3. Paste this command:

.\steamcmd.exe +login YourUsername YourPassword +workshop_build_item D:\mods\tka_mod.vdf +quit

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Notes:

A. "YourUsername YourPassword" <- This is the login information for your Steam account.

B. "D:\mods\tka_mod.vdf" <- This is the exact file path to the .vdf text document that we created earlier.
___________________________________________________________

4. Press Enter to begin uploading to Steam Workshop.

If you have the Steam app installed to your phone, you will receive a Steam Guard prompt to verify an attempted login. Allow this login to confirm the upload.

Once verified, the mod will begin uploading to the workshop. Once Command Prompt finishes publishing, you can now view your new TKA Workshop item (change the title, write a description, add additional photos, write patch notes, etc).

To update an existing workshop item, replace the .pak file in your Paks folder and run the upload command again.

As long as the ID for "Published" in the .vdf file has not been changed, it will overwrite your existing workshop item with your new .pak file.

Now go make some mods! 😊