Re: New to the Black Rifle world and need advice.
The first thing you can do is get a railed forearm. Without the rails you will be very limited in terms of accessories. If your upper already has rails, I can recommend getting a vertical grip(personal preference) for consistent grip on your new black rifle. You can then add lights, lasers, or optics it all depends on what you want your rifle to do. The above optics are all great options. The possibilities are really endless with an AR15 so go at it and have fun.
Good luck