Instructional Material
Although the RV wing kit includes the RV-12 Wing Plans and the "Standard Aircraft Handbook", you may want some additional basic reference texts such as:
"Kit Airplane Construction" 3rd edition, Ronald J. Wanttaja, McGrawHill
"Aircraft Structural Technician", Dale Hurst, Avotek
If you are hands on learner, consider taking a Fundamentals Class from a builder such as Synergy Air and/or purchasing the excellent DVD "Air Sheet Metal Tools" available from Van's. The EAA has an excellent series of online videos for homebuilders.