There will be no need to adjust the needle if it is on the stock setting of the middle clip.
If you do ever need to adjust it, down inside the slide there is a removable clip.
The spring has to be lifted up out of the way and the clip removed, this will allow removal of the cable. This job is easier if you have 3 hands.
Take out the 2 phillips head screws and remove the retaining plate.
The needle can now be lifted out, take notice the position of the plastic washer around the needle, it has to go back in the same place, above the clip if my memory serves me right.
The clip can now be taken off and replaced where you need it.
Beware the clip has a habit of taking unannounced flying lessons, I usually surround it with a bit of rag to stop it taking off.
Reassemble in the reverse order.
By the way the only dumb question is the one that is not asked!