How to make a chassis from scratch

From Crankshaft Coalition Wiki

hello am new to this my name is graham i have been looking for a project to do and ive have decided to design and make a custom rod from scratch but i havent done this kind of project before so i would need a little infomation if that ok ive seen lot of people who make chassis but i want want to try it for satisfaction i have been looking at boxed section steel but am not sure where to put the cross members or anything like that or the diamentions the will be low it will be roughly the size as a lambo ( lengh, width) thank to anyone who can help