Where can I find the best site to learn aircraft design on a small scale? I am undergraduate student still trying to figure out a lot about Aerodynamics and aircraft design. I am learning how to design rc planes.

So the thing I know the weight of my plane which is between 700 gm to 1000 gm and velocity which is 13 m/s.

I just know the basics that is the lift formula and other fundamentals. I want to know how to design a nice fuselage for my plane and also how to keep balance in my plane. I seriously need help and also there are courses where you learn all this, but they ask for heavy cash.
It's not a website, but it's totally worth buying: Dan Raymer's Simplified Aircraft Design for Homebuilders (ISBN 10: 0972239707  ISBN 13: 9780972239707) is applicable to RC aircraft and has the best ratio of comprehensive coverage to beginner-friendliness of any resource I know.