Does anybody know any tutorial on how to model car in CAD from skecth(no blueprint)?
You would want to create orthographic sketches to act as your blueprint. It often helps to find a vehicle blueprint which has similar dimensions/proportions to what you want to model, since this lets you reference something that is accurately dimensioned in your sketches.
Then import your orthographic views and line them up (there are tons of tutorials on this online if you’re unfamiliar with it) and start modelling.
Your sketches may not be completely accurate, but it should be a decent place to start. You also only need to draw half the car for your front/rear/top views as you can just mirror these in photoshop or mirror your geometry in 3D.