Me getting an Ar-15

[hotborad]

So im new to the rifle and shotgun world. I'm well knowledged with my pistols. But I never received a gun license because the guns were manufactured and bought before any of the gun laws where implemented. Im interested in buying an AR-15 online because none of the dealers near me have any AKA I live in the boones.
Here are the specs im interested in also where to buy beside http://www.ar15builder.com/

-11.5inch barrel
-carbine handrail
-flattop receiver
-standard lower receiver
-adjustable stock
-10round magazine .22lr with conversion

Any tips or suggestions would be great also how do i get the FFL for online purchase Id rather just fill it out in store and stuff but id rather have the gun fully assembled. But so far i have yet to find a full assembled AR-15 with a 11.5 barrel. Also a concern of mine is not having all the parts for the gun having to buy more parts not knowing if their right sizes etc...