Hello and welcome!
Using parts from part-sheets does not require crediting, but taking chunks from ships by other authors does. Hulls for ships aren't found in sheets, as they are way too large and frankly no two hulls are exactly the same, and thus they are drawn from scratch.
As for tutorials, there is only a style guide which I'd say is quite important and very informative.
I personally I use MSpaint as it's quick and simple. There is a 'curve' tool too and straight lines should not be hard at all if you are zoomed in and can see what you are doing
Anyways I'd love to see what you come up with. Starting off with AU ships is perfectly fine (I did that), but some members here recommend attempting a real drawing as it's REALLY good practice.