A couple ways to answer this:
1. if you want the easiest path, then a two piece system that is commonly referred to as "drop-ins" are the easiest. It can be as cheap as a magpul moe or as expensive as the daniel defense or the knights armament.
a. pros: easiest to install because it uses existing hardware and no additional tools needed. So you won't need to removel the front sight at all. FYI, this is the sort of system that is currently on the M4 because the pinned fsb is considered to be the most reliable system.
b. cons: theoretically not as accurate because it's not free floated, but i think this point can be a bit overplayed/overrated. Is the statement true, yes but the difference is marginal and there are benefits. Besides, the standard marine can hit a man sized target at 300yards on open sights while sitting on ground. So that's good enough accuracy for a battle/tactical rifle.
2. The free float is the other options. This is a more modern system and lends itself to accuracy and tricking out your rifle. But this will require more work and tools if you don't have some already.
a. pros: like bolt guns, free floating maximizes the accuracy of a rifle. There are far more free float options available than drop-in potions these days.
b. cons: Significantly more work than option 1. A few of the free float system will use the same barrel nut that comes standard, but you have to remove the delta ring assembly. Most free float systems require a special proprietary barrel nut system to attach the barrel to the receiver and the handguard onto the barrel nut. So you have to remove the current barrel nut and use theirs. Any free float system will require you to remove your fsb, which means you have drive out the pins and slip the thing off. Oh, and you're gonna at least need to borrow or buy an ar armorer's wrench and something to hold the upper receiver/barrel while you do all this.
If it were me, I'd do a simple drop in Magpul Moe. It's cheap, around $30 sometimes. It has some limited ability for attachments; grip, lights, bipood mount. Super easy to install. Won't win you any benchrest rifle competitions in accuracy, but it will get the job done.https://www.magpul.com/products/moe-mlok-hand-guard-carbine-length-ar15-m4