1.
https://github.com/Reagy/TF2Classic-KO-Custom-Weapons 2. Click "Code" -> "Download ZIP" (~1.5 GB)
3. Open in your favourite ZIP tool (7zip, winrar, windows probably has a built in one too idk)
4. Navigate to TF2Classic-KO-Custom-Weapons-main/assets_server
5. Extract the folders materials, models, and sound into tf2classic folder where folders with the same names should already be