yep, your bowden box is wrong.
I dont find it one of the easiest tasks.....
On the underside of the battery tray is a holder that the bowden box slides in to.
Install the battery tray / frame.
On the right hand side, there is access, you may need to hold a rubber pipe out of the way. Push the left side throttle body cable through (and the high speed idle cable) and then slide the box in.
The cable from the twist grip and the right side throttle body cable exit out of the right side.
When you ahve it in place, check and make sure that each of the cables enters and exits the bowden box to the throttle body with nice smooth curves and no kinks.
you can also put the bowden box in to the underside of the battery tray frame and then install it.
I dont know which way is easier.
It is fiddally and a bitch of a task, but do able, have done it a few times.
Whilst we are talking about throttle cables, DONT lube them DONT put any oil or other stuff down them. The PTFE liners will gum up if you do and make them worse.
Because its a bitch of a task and if you think that you need to replace the throttle cables, best to do it now rather than have to pull them again.
If you are going to change them, I would recomened you do all three, dont know about the fast idle, I dont use it where I live