i need help skinning!!

[SiiK FO]

where do i add the dds plug in into photoshop?
here are the options where i can drag it into

3d engines
adm
automate
effects
extinsions
file formats
filters
image stacks
import-export
measurments
panels

[Soviet]

file formats.

[SiiK FO]

i did but when i try to open a cod4 weapon in it it says wrong document

[Soviet]

Did you convert it from IWI to DDS?