The Scarab will be a significant step up from a kayak, but probably not too big if you were doing aircraft.

Sailing is not too hard to learn, the first lesson is to always head upwind when you start, that way you have a chance of returning to port if there is trouble.
You can probably find some kind soul who will inspect the boat when it's finished for beginner errors, and take you out the first time. Is there a yacht club near by?
The hardest thing for most to learn is "where is the wind coming from" because wind direction vs boat direction is what indicates how you sail for the moment.

Qualify of boat plans varies considerably, your best bet is to get the study plans, and see if you can find a build blog where you can ask questions. That is a plywood boat, possibly you can find someone who will NC cut the panels which will eliminate lots of errors and speed up the build.

You may find more focused information from:
http://forum.woodenboat.com/index.php
http://www.boatdesign.net/forums/

I have not seen a reference to a build blog on either site recently.

I'm interested in what aircraft you were building. :)

Good luck