Plugin comes in four different versions for the different supported 3ds max versions. Additionally, there are 32 bit and 64 bit versions for all max versions.
Choose the matching folder and copy the file meshak.dlm from into your plugins directory.
Copy the file "meshak.chm" into your help directory.
Restart max. The modifier is now available
as "Mesh AK" under "Max Edit". Additionally, the vertex paint mode of
Mesh Army Knife is available as a standalone modifier "VertPaint", and
the Sculpt mode is also available as "Sculpt".