Does someone know how to upload an item to the workshop?

More specifically an overwrite of an already in game item for my server as I am trying to add a crafting recipe that comes from another mod. To be more specific, I added a crafting recipe to the Military Ammo Box to be able to take ammo from a M-CAB (from the SOUNDS OF FREEDOM mod) and transfer ammo to it. I also added recipes to the M-CAB to be able to fill military mags.