I've only made a handful of boxes- all the hewn out type, but I would say just dig in there and make some. I think you will learn more about how boxes work if you make a hewn call. You learn a lot from little changes in soundboard diameter and radius etc.
For starting out, get some less expensive blanks (poplar etc) and expect to make some firewood. Also, as you're learning, buy a pre-formed paddle, or take one off another call. That way you're only dealing with one variable (the soundboards) and not two (the boards and paddle). After you get a reasonable sound you can make your own paddle. Otherwise if you make them both at the same time, it will be much harder for you to figure out which is affecting the sound you're getting.
Like I said, I only make 1 or so a year (just finishing this years'). They are fun because the sound is 100% from your craftsmanship, but man can they be humbling. I'm constantly amazed at some of the ones that are posted on here that look and sound amazing. Hopefully you get some tips from some of the more experienced makers as well. Good luck!