If you can, find a library with a copy of
Hucho's book and camp out until your head is full of ideas backed with data.
Once you have an outer shell you like (including wheels, fender cutouts or skirts, cooling flow accommodations, etc), use Sketchup to package the major components - drivetrain, radiator, fuel tank, driver & passengers. This is, of course, a big project. I've done it a few times
The modeling phase will save you a lot of rework if you put some effort into it.
I remember hearing of the demise of a human powered submarine team in college, that had a great sub, looked beautiful in CAD, but when they built it, the pilot's heels would hit the shell when he tried to turn the pedals. Oops.
Endless lessons await you. Enjoy!