Elevator assembly is straightforward, but you have to carefully study and understand several details, to avoid pitfalls.
The current version of the Sling 2 Empennage Construction Manual leaves much to the imagination of the builder. Build sequence details are very important. The written steps are basically in the proper order, but the labels (numbered bubble call-outs) are not to be relied upon. I had to cross-reference several pages to figure out exactly what parts were referenced in each written assembly step.
If one is not very careful, it is easy to rivet together parts prematurely and/or to occupy holes that need to be left open for later steps. Even the factory has trouble with this. I have more than a few rivets to drill out and remove on my QB fuselage, in order for me to rework factory build issues. Take time to understand what exactly has to happen to achieve the correct result.