Welcome aboard.
There are some people here who enjoy designing planes and others who don't want to design, build, or even know what makes a plane fly.
Designing planes and flying them are very different activities... they both give you some useful information to use for the other, but neither one can prepare you for the other, and they each make good hobbies. I thing it is great that you're going to try designing your own.
The basic sizes and proportions for most planes are reused with only small changes... they can be found at Howard Sullivan's
R/C Fight Unlimited site. There you will find a lot of information on many topics of interest to R/C people. There are also plans available on the web. The best way to produce a good self-designed plane is to start with a plane that's proven to fly well and change it to look the way you want without changing airfoils, angles, and areas of its flying surfaces. A super source for plans is
http://www.aerotech-rc.com/. Another big plan site is the
Airplan Man site. MAny of these you'll need a CAD program to manipulate, but there are free viewers available on the web that should also allow you to print the plans (you may or may not be able to control the size of the printing.) A final source you'll like is the
UIUC Airfoil Site... It's full of coordinaltes and graphics defining zillions of standard airfoils and a lot of non-standard ones... many many hundreds of them as well as free trial software downloads to examine, compare, design, and print airfoils.
On airfoils, when all is said and done most of todays models use the NACA 2412 or a near relative for "semi-symmetrical" foils and the Clark-Y or a near relative for "flat-bottomed" airfoils... and millions of dollars' worth of research has been devoted to finding better things to use, but after 80 years of trying, it hasn't really found much better so far. You or I may be able to better that record, but it is not likely.
Anyway, have fun, use the wisdom that others have imbedded in the many free plans you can download, ask questions and, again, have fun.