@Arkandias Okay I'll try to answer your questions, I actually had to give the latest version of the game a try myself since I haven't played for a while and the sleep mechanic is comparatively new, then I got lost in exploring some new stuff I hadn't seen before.
1: The command is rest. If you rest correctly you gain the ~"well rested feat" which gives you a plus two to all stats, which also equalises combat a little. I do admit the "your not drowsy" response for sleep or nap is confusing.
The reason it isn't working correctly is that either you have run into a bug, or more likely you don't have the cot with you.
If you don't have the "roughing it" feat or the cot in your inventory resting won't restore anything. If you do have either the cot or "roughing" it" and your not seeing the "well rested feat" turn up after you rest (check the "look me" command), then its possible you have got a bug somewhere and should report it on the fs forum.
2: typing "nav" on its own brings up a list of locations, they're organised by district, EG "high rise, Zephyr" New locations you find or hear about will turn up on that list, or if you have the "city map" feat you'll see everything.
~Typing "nav" and the name of a location will try to travel to that location (possibly running into trouble along the way). So, to get to Zephyr type "nav zephyr" (be sure on spelling and typing everything since the game needs precise input).
The scientist you heard mentioned can be found in Trevor labs, which should appear on your map after you hear about it, so just type "nav trevor"
About hunting and exploring.
When your at a nav point, (when you see "explore" and "nav" listed as exits like in the central room of the grey abby library), you can type explore to run into a random creature or event, or hunt and then "event/creature/location" to look specifically, though it takes a perception check.
Bare in mind though that unless your playing in hard mode, most higher level creatures won't show up until your ready for them. If I remember rightly the Panthertaurs Larissa at Zephyr tells you to hunt are level 4, and don't show up until you hit level 1 or 2.
if you want a good start off quest, go to trevor labs and see Dr. Mat.
Also, note that as well as the huge over world with its events and creatures, there are also individual hunting areas in most locations in the game too with their own set of monsters and events, for example if you go into the mall and go east from the foyer, you can go east into the public toilets use "explore" to check out the sewers, you'll need to do this to find one of the monsters for Dr. Matt's quest.
The one mildly annoying part of the game is that currently there isn't a way to track what quests you have or get details about them, though I know a quest tracker is in the works.
if your stuck on what to do try The Flexible survival wiki found here though read with care since finding things out for yourself is always more fun.
Okay, to answer your rp questions.
If you start in Bunker mode you begin with a human form, however yes you've already been infected. Your libido will rise over time and you will find yourself getting mutated somewhere, this is all part of the game, since the idea is that each mutation carries a strain of the nanite virus which is trying to propergate itself and prove superior over other mutations hence the rather overthetop urges to, mmmm, breed.
If you really want to stay human in form, try playing in researcher mode, though mutating is all part of the game's atmosphere, indeed my character on the fs mud is someone who was ravaged by a next door neighbor, and has now done a deal with Zephyr to get nanite shifting powers so she/he can take on whatever form she/he wants from any creature she/he defeats, ditto with the change in gender.
This is just part of the game's ethos, and how much you give in to it is up to your playing style and personality. I personally always see the goal here as basically trying to maintain some sort of equilibrium despite the crazy new way things are going as well as making a safe haven for other survivors and generally helping out where I can, but you do have some less pleasant options on occasion, some of which you might find yourself giving in to if your libido is too high whether you want to or not (though you can take feats to change this if you wish).
for a good idea of the game's world and ethos, go and check out The SMithhaven Mall and talk to the people around there.
Hth.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)