CMYK in GIMP ? I need to pass a gimp file to cmyk

How do i achieve this ?

You could try this, but they are experimental:-

If you’re looking to try the separate+ plugin, this blog post and comments might be helpful.

you can do it with nodes, i think. yellow is the red and green passes added and ramped. (use the separate YRGB). B is just Y, M is R&B, and C is G&B.

ImageMagick can convert from rgb to cmyk:
convert yourRGB.jpg -colorspace CMYK yourCMYK.jpg

Can you post a setup ¿ and , mean in gimp, can you explain more ?