Being a nooB, I have no idea what this is used for. I tried searching, but came up with nothing as far as what it's purpose is. thanks!

to assist the forward motion of the bolt group.



helps it home.
also to silently send the bolt home with a nudge instead of slamming it home.

So upon pulling the charging handle, you would slap the FA with your palm to help it "home"?

Is this how it is used?

to give you something other than the trigger to play with when you are nervous.
sometimes the bolt ont always close all the way, so you use that to assist it in moving forwards.  I personally use it alot- after checking the chamber to be sure a round is seated there is not always enough force in the spring to push the bolt forwards all the way, so yyou use the forward assist to nudge it up...

When the AR15/M16 first came out it did not have this feature.  Combat operations showed that there required a way to seat the bolt all the way forward (locking it) due to fouling, dirt, etc.  It serves the same purpose if you have a manual bolt action, or a auto with a operating rod (M1, M1 Carbine, M14 etc) where you hit the charging handle to seat.  As mentioned it can also be used when silence is required to chamber a round and to do a press check before you know your going into a hot situation.

CD

It is also great for "brass checks" when you are making sure you have a round in the chamber.  Some guns that are tight, new or a bit dirty need a little bit of puch to reseat the bolt when you do this.  The FA is perfect for that.

REMEMBER THIS: NEVER HIT the FA, just push it with your thumb lightly.  If, when you are loading from a fresh mag or in the middle of a string of rounds, the bolt will not seat with light pressure on the FA then you need to eject that round and go to the next one.  It ( the cartridge ) may be damaged.  Hitting the FA will jam the weapon by ramming a deformed cartridge into the chamber.  I learned this from experience.