5D Embroidery Plus is sold separately, 4D File Assistant would not work with 5D Design Enhance is part of the Pro version. Once someone who owned it earlier has registered the module(s) you can't register again and you need the original dongle.
I am afraid 5D is outdated, 6D is still available although the upgrade to Premier Plus can be bought - the new program will be available shortly.
I own 5D and 6D, both the Pro versions - the dongle works for both. And 5D Quilt System which has its own dongle.
There is a 5DEmbroidery Yahoo group that has all sorts of information in their database and if your question is not there you can ask the question and usually get more than one answer.
Welcome to Cute.
I'm sorry I can't help, but there are quite a few 5D users here who will be along soon.
In the meantime, why not browse around the site? The Q&A section will show you how everything works.