1) Go to C:\Program Files\Steam\steamapps\common\left 4 dead\left4dead\materials\models\infected\smoker and put the the included file in the smoker folder, make sure to backup your old file incase you want to revert back to original skin.
2) Now, look for "whitelist.cfg" and add "add" "materials/models/..." under the line // Additional files/directories to allow. Be to make a copy of this in case something goes wrong.
now if you useing more than one skin do the following step
3) look for pak01dir.vpk in the left 4 dead folder you will know your there when you see all the other pak files. Open it using Notepad ++ to open it. Make sure you backup the original pak01dir.vpk file.
4) Now hold down the ctrl key and the letter f at the same time, then type smoker in search box then click find when you see the line:
you should change this line to this:
if you just want the smoker skin back up your original
pak01_dir.vpk & "whitelist.cfg"
and then just put the included:
pak01_dir.vpk & "whitelist.cfg" in the left 4 dead folder.
intructions included in skin pack