The build shop gives you a kit that's structurally complete, but missing all the details. Now comes the hard part - making all the straight pieces and edges really straight, making the elevator and rudder gaps straight and even, filling in all the little visible areas at the end of the horizontal tail spar, inboard edges of the elevators, making all the skin joints smooth, cleaning up the horizontal-fuselage fillet, making all the access panels fit properly, ETC. ETC. If you can see it, feel it, or move it, it needs to be nicely done.
We start by finishing the rudder assembly that was cut off at the build shop
There is a lot of filling and sanding to make it flat, not to mention fitting it to the vertical stabilizer
Then there are a couple of access panels to fit and install nut plates. The recess around the plates have a lot of voids that need to be sanded out and filled
After installing the leading edge fillets and filling/sanding, a little primer helps to find spots that need more work
Meanwhile, the elevators get the same treatment as the rudder - making them fit nicely and filling in low spots
The rudder gets more fitting when the fuselage is upside down.
Also working on the bottom of the horizontal stabilizer-fuselage finishing
It turns out that we need to widen the gap between the horiz and elevator, so a little strip of carbon is added
And the rudder hinges are a little off center, so the middle one is shimmed to line them up
The tail is starting to look like it's supposed to.. but not done yet
We need little more gap on the top too, so adding some carbon, sanding for a straight and even edge
Since we just want to add a little micro, some thin beads of micro are put on, sanded to the approximate thickness, and used as guides
So that we can put on just about the right amount of micro - saves a lot of sanding
Similarly, the surfaces of the elevators are built up a little to make them straight when sanded to fit the elevator. The elevator must move full travel with a consistent gap
Unfortunately, there don't seem to be any "intermediate" pictures, so hopefully this will help