Back-flat and other accessory modding

[Buiilder]

Hello,

I am a French amateur modder which begins in the universe of the modding on pc. I shall wish to provide to put my paper creation on software (Adobe Illustrator) but I do not know how to use it to have the same depiction as my sketches. You can advise to me to improve me or give me of the tricks or videos explanatory who would allow me being able to move forward? 

Thank you