I have no direct answer because there's about 10 things you could get wrong JUST with file permissions. Additionally, FreeNAS is marketed for enterprises and businesses. Not so much for home users, but it does work for home users that are going to take the time to learn the appropriate hardware and use the software properly. Most "home users" aren't quick to run out and buy server-grade hardware for a file server.
The documentation isn't exactly lacking on stuff, you just don't sound ready to sit down and read the manual and learn how to use it in a VM. Learning a new OS(especially one as technical as FreeNAS) isn't going to come in a week. And depending on how dedicated and how good you are at learning new skills you may pick it up in a few weeks or you may never pick it up. FreeNAS isn't for everyone and plenty of people that don't have the dedication and intelligence find other software solutions are better. You've probably taken years to get where you are in Windows. As such, you should not even come close to expecting to be a pro on a new OS in a few weeks. If that reality isn't good enough, Windows does offer Server solutions. They may be expensive and bloated, but that's the tradeoff. Some people will find that the tradeoff in time spent learning FreeNAS is well worth it. Other's would rather buy Windows and not spend their time learning a new OS. You'll have to make the decision for yourself as to if FreeNAS is for you or not. I think I did very well at learning the basics with just 1 month to learn it. I'm not sure I've found anyone that has beaten me for knowledge in the time specified. But feel free to spend as much time or as little time on it as you want. You can also optionally pay someone to build your server if you don't want to spend your time on it. Everyone knows the phrase "time = money" and this is no different.
Me personally, I took the manual from 8.0.4 and a month later had a server running better than my Windows server on less hardware, did everything I wanted, and required little help from the forum except to validate some assumptions and bugs in the software. Not to mention the 8.0.4 manual wasn't as good as the current manual and there were the forum stickies to help you learn alot of the stuff that people get wrong. Then, after I got FreeNAS up and running I've spent significant time putting together my noobie presentation which obviously didn't exist for me to learn from since I wrote it.
So feel free to use the manual and ask questions specific to error messages and issues you are encountering. But threads like "FTP is broken" isn't going to give you an answer as it lacks any kind of specific information to begin troubleshooting your problem. That's like me saying "my car won't work". Ok.. that's a bit too vague to begin to diagnose a problem.