Hi Marnivi good place to start would be Toms kite building site, process of building kite from scratch. It will answer all your questions leading edges, cutting cloth.Also kite plans for print on a4 tape together.
In the past built open source kite plans the Return from kareloh.com is great, but you will require print shop to produce full size plans? Over the years even with using China Icarex (pc20) it can very easily become a costly Hobby!
oh thank you very much, I had no idea about that site, it's just what I needed, thank you!