I am interested in making some custom ships and weapons for use in my server. Is there a guide or something where I can learn how to do this?

From what I can guess this consists of taking a CAD drawing and a file with the ship info. Would there be a way to take the images of existing ships but change their info, for example taking a freighter and adding armor and more powerful guns so it is a gunboat?

Thanks, and if there is already a thread aobut this i'm sorry.