Below are the throttle settings I have. Note that when the throttle is centered you are at zero. Moving the throttle up you go forward. Moving the throttle down you go backwards.
Also note that when you start the game you may need to set your speed to zero as soon as you launch. I have had installs that if you start the game and launch your ship your ship will immediately start moving and you need to set your speed to zero immediately. After you set your speed to zero you can then use the throttle on your JS. You should only need to do this when you first launch the game and I only needed to do it the first time I launched the game after I had turned off my PC.
Also note that in ED Controls Settings when you make any changes and press the apply button then you have just created custom settings and this is what you need to leave it set to in ED Controls. Every time you go back and set it to generic JS you just deleted all changes you made.
I do not use the Logitech game software, you don't need it. All changes you need to make can be made under the ED Controls settings menu.