After downloading the mod, use a program such as 7zip or WinRAR to extract the main folder of the mod.
Move the main folder of the mod to assets/mod_overrides. The assets folder is supposed to be in your game's installation folder (don't know where that is? click here for PAYDAY2 folder). Create the folder if necessary
pop this baby in mod_overrides and bada bing bada boom it works*
*in the main menu go to options/sound/custom menu tracks and replace master plan with this one. or dont im a sign not a cop