Qustion on shipsets / How to use ?

Hi to all,
I haven't played for a long time due to lack of same I.
I wish I could use the ship design feature (which is great),
but I lack TIME and also my artistic skills leave a lot to be
desired (given a lot of time I could come up with something useful,
but there it is, lack of time, the bane of any employed person).

I would like to use the nice shipsets available in the library,
but have not yet really figured out how to use them.
As of this I would ask for how to use them,
(possibly with an actual download as example).

Furthermore, would it be possible to use more than one set/ship model
in the same game as there seem to be some different sets
(e.g. small and large terran style ships, B5, ST,SW) and possibly other
items.

I would like to use something like nicly designed base hulls,
to which I could add the parts like sensors, weapons etc.

If this possibly dumb question had already been discussed
please point me to the respective thread. I couldn't find one.

Thanks for any help.