Good morning Joeseph. To add sights to an AR is super easy. The piccatinny rail on top of the barrel is slotted allowing you to mount up either scope rings, a Red dot or the basic sights which I definitely suggest putting on first. I actually have the pair of MagPul MBUS sights that Ed C. Suggested. They went on easy and are simple to adjust.
Have a great day!

Joseph, it is not difficult at all. The sights attach right to the picatinny rail on the top. I would stay away from spring loaded flip up sights. I recommend Magpul, you'll have to buy F&R separately.
Front - budsgunshop.com/product_info.php/products_id/1135/magpul+mag247-blk+front+mbus+gen+ii+black ,
Rear - budsgunshop.com/product_info.php/products_id/1132/magpul+mag248-blk+rear+mbus+gen+ii+black ,
Stay safe & have a great day!

Joseph, very simple to add sights. If you look at the picture there's grooves at the top of the receiver and handguard. That's the picatinny rail and how you'll add sights and scopes. You just have to loosen the screw on the sight, line it up on the picatinny rail and tighten the screw back up. I'd recommend adding the front sight as far forward as you can and the rear sight as far back as you can. The more distance there is between the sights will help with accuracy. As for Wich brand I'd highly recommend Magpul mbus sights. Here's a link to the rear sight........................... budsgunshop.com/product_info.php/products_id/1132/magpul+mag248-blk+rear+mbus+gen+ii+black .......................... And here's a link to the front sight........................... budsgunshop.com/product_info.php/products_id/1135/magpul+mag247-blk+front+mbus+gen+ii+black ............................. If you would prefer a scope here's a link to a Bushnell 1-4 ar optic specifically designed for AR-15s........................... budsgunshop.com/product_info.php/products_id/104969/bushnell+ar71424+ar+optics+1-4x24+obj+112-27+ft+@+100+yds+fov+30mm+tube+dia+black+matte+drop+zone+223 ...................... Hope this helps.

Hi Joseph and welcome. Very easy and takes about 3 minutes. I have a similar Radical AR and went with these sights : budsgunshop.com/product_info.php/products_id/132557/ncstar+vism+flip+up+front+rear+sights+black+flip+up+steel+aluminum+ar-platform - Cheers and stay safe!