To my knowledge there is no tutorial on how to scratchbuild any sort of ship, either on our site (modelwarships.com) or any of the others.
If you don't have experience in scratchbuilding (I'm assuming because you want a tutorial you don't) then my best advice is to start out with something simpler than a carrier.
Having said this, I've scratchbuilt about 15 ships so far, including 3 carriers. It's time consuming, frustrating, and requires a ton of patience and research...and I pretend to know what I'm doing.
If I can be of help, let me know.
Jeff Herne
Modelwarships.com