There are two versions of NSE, classic and 2.x. While classic does have the ability to edit the backsprites, I recommend you use 2.x. You're probably using the "Minisprite" version [Classic]
You can grab NSE 2.X here or in the toolbox.
Load your ROM in NSE 2.X, then click File>Navigate.
To the right, in the Navigate window, is a grey folder called POKEMON Open it, then open to BPRE/BackSprites.
There are folders containing all of the backsprites in firered.
NSE 2.X lets you edit all of the back-sprites and their palettes directly within the interface, no need to import or export anything!
Oh!!!! I see :D
But this one wasn't made by DawnRyder and I like her tutorials since they're simpler and easier. Which is why I was anticipating her next tut for so long xD
But thanks for redirecting me there anyway. Now I can finally complete my titlescreen hack