These are your supplies
Turn the dock over and notice the black cover plate.
Unscrew both screws and take the cover plate out.
The black cover plate has 2 sides. Hold it like this with the flat side up and push the reinforced part of the cable into the slot.
Then next insert the assembly into the dock like this.
Screw the 2 brass plated screws back in to secure the dock. Don't over tighten.
Push the cable towards the slot firmly.
And guide the cable into the slot as deep as possible. I always do it clockwise but that of course is up to you.
I always give it one and a half turn. This seems best those cure the able in the slot.
And lead it out in the back.
And voila! You are done and ready to put your iPad Air into the dock.
The best way to do this to use both hands like this and gently slid the air onto the lightning plug into the dock.
And this is how it wit will look. Enjoy!