Mercury Mod Manager
If you have Mercury Mod Manager installed extract the contents into .../PAYDAY3/Binaries/Win64/Mods or .../PAYDAY3/Binaries/WinGDK/Mods

Manual
If you don't use Mercury Mod Manager or prefer to just use the default UE4 pak mounting extract the contents and move the mod .pak file into .../PAYDAY3/Content/Paks/~mods. Create the folder if necessary.