Wing halves are the easy part. Read forward in your instruction manual to see what the procedures are to install the rudder and elevator. Most of the time, elevator installation requires that you have the wing attached so that you can make sure you get the elevator lined up centerline of the fuselage. There should be some description as to how to do that. If not, let me know and I'll walk you through it. The next fun part is engine installation, and that usually just requires making sure you get the holes lined up correctly on the motor mount, it's really not that hard. Just ask me the questions if you need to, PM me for more detailed info.