Before you get started you will need to download the following.

• GCFScape
  
• FFOF Fistful of Frags
  
• A text editor
  
  Most people will have the last two but the first one will get most people.If you don't have GCFScape then download it here http://nemesis.thewavelength.net/index.php?p=26 . IMPORTANT: YOU MUST CLICK INSTALLER NOT ARCHIVE. Go through the installation process and proceed to the next section.
  

Now that your ready to create your mod, you gotta decide what to do. For example I will just do a sound replacment mod. Optional First off make a folder where all your mod assets will be, say perhaps your C drive ( for convenience ). Next, open GCFScape and locate your steam install then proceed to \Steam\steamapps\common\Fistful of Frags\fof. Then open Fof_dir.vpk. This should pop up in the bottom " Frags\fof\fof_dir.vpk loaded ". Once opened right click the folder called sound ( Or whatever you wanna change / add ) and press extract, Put it in your Mod folder ( Or wherever you want too ) and proceed to next section.

Create a folder of the name of your mod, For example "MySoundPack" in your mod folder. Then in the folder you just created create a folder called sound ( Or whatever you wanted to change ). Find the sound you want to change, Ill change the axe hit sound. Now put down every single folder that leads to it. For example the axe hit sound has three states, I'm only changing one. It is called axe_hit1.wav. Keep in mind the wav part of it. Since its located in sound > weapons > melee, You have to go to your mod folder and put a weapons folder go inside that one then put a melee folder and then go into that one. Once your there proceed to the next section.

Now that you have the name of the sound you want to replace and the folders setup, Now its time to find the sound you want to replace it with. Note: Any sound file you want to use has to meet 2 conditions: A 44.1k sample rate and the file has to match the games' sound file's extension. Not sure if the 44.1k sample rate one is right but it does have to match the file extension, Say it was axe_hit1.wav then what your replacing it with has to be a wav file, Same for mp3 and etc. Put your sound there ( That you want to replace the original with ) and rename it to the original. Example: rename iDubbzdance.wav to axe_hit1.wav . Once done copy your WHOLE FOLDER to the custom folder in fof where you found Fof_dir.vpk. Then start the game and test out whatever you changed in the game. Note: This mod is Your OWN Mod and is not on the workshop. Please refer to the next section to see how to publish.

First go to Fistful of Frags/sdk/bin then locate vpk.exe, Then drag and drop your mod folder ON TOP of the vpk.exe program. Do not launch the application it wont work. Then you should see 'Your mods name'.vpk in your mod folder ( WHICH I told you to make ).
Once your done with everything and want to publish your mod, open your text editor and copy "
ugc_create "path-to-content" "path-to-preview-image" "Title" "Description" " Then edit everything to your mods path, picture path, title, and description. Example: ugc_create "c:\mods\mymod.vpk" "c:\mods\mymod_preview.jpg" "Best ever mod" "Not much more to say". Then copy that go into FFOF and paste it in the console. When you come back BOOM your mod is on the workshop.GOOD JOB! ( haha jk ).