Gimp Rawtherapee link

I am at my wits end I have been trying for a week to get Gimp to open my raw files (Nef) with no success
I can find my around my pc but i don’t have a clue about open source code so I’m looking for some one to explain to me in simple terms how I can get a raw file open in gimp with Rawtherapee.
I’m running windows 10 Gimp version 2.10 and Rawtherapee 5.4
I’ve tried all sorts of configurations in the preferences of RT external editor section I just can’t work out what to do.
I’ve been searching the internet for a week and I can’t find a simple step by step explanation on how to link Gimp and RT can someone please HELP!!!

do you have spaces or non ASCII characters in your user name or the path to GIMP/RawTherapee?

I’m not sure about ASCII I’m just going from RT preferences/General Tab/External Editor/Gimp Installation Directory/C: Drive/Program Files/Gimp 2.0
Do I have to go further in to the program files?
If I go C: Drive/Users/Name Gimp does not show in the folder

You need to go all the way to gimp.exe

http://rawpedia.rawtherapee.com/Preferences#External_Editor

YES SUCCESS!!
Kind of. I created a custom path to gimp and the photo opens in gimp the only thing is the photo has been converted to a tiff.
I thought gimp 2.10 supported nef files?
So which program is converting to tiff RT or gimp and how do I stop it?

GIMP itself does not handle raw images. GIMP comes with a plugin called nuRaw that gives extremely simple raw development options. You can also use RawTherapee as a gimp plugin. As you’ve noted, RT converts the image to tiff and passes it to gimp. You’re much better off with RT than with NuRaw IMHO.