sometimes the mods wont install from the workshop after you clicked subscribe and you will need to install them yourself. most will come with a direct download link to the mod. click the link to download the mod. extract the mod and click the readme file or instructions file to see how to install it. for maps they go in the C:\Program Files (x86)\Steam\steamapps\common\KillingFloor\Maps folder. if there is no instructions to install the mods or maps then check on the steam page the mod is on and the developer probably left instructions. after you put the map or mod files in the correct folder open kf. on single player click the mutators tab. check off the mod name that you want to use and pick the map and diffucalty etc. start the game and it should work. any more questions just lmk.

Thank you Ocular that was very helpful.