I'm assuming you have a carbine (very short handguard)
You have two options with YHM.
1.They make a free float version (all one piece - mounts as a sleeve, over barrel, attaches at base of barrel, via a locking nut)
2.They make a 2-piece that mounts just like the plastic handguards, under the delta ring (the spring held piece that holds your handguards in currently)
What are you going to do with your gun? are you planning to mount optics on your handguardse? If not, I'd go the 2-piece, as you can do the swap with no tools. If you want a free float system, you will have to do some disassembly of your barrel. You need to remove the front sight base, and buy a special wrench to tighten the free float retaining nut. It is not impossible and folks here can talk you through it, if you want to try. The one thing that could be an issue would be a permanently mounted muzzle device like brake or suppressor, which are pressed or pinned/welded sometimes, and have to be removed (I think) to get the free float nut onto the barrel.
FWIW, I have the 2 piece mount and am very, very satisfied with it.
It is sturdy as hell. I did have to torque down my barrel nut a tiny bit to get my handguard to match my A4 rail to match the YHM rail and get them lined up perfectly. (the YHM 2 piece indexes of of your barrel nut - that sprocket looking thing) with some pins. So the barrel nut must be perfectly aligned to have your handguards perfectly aligned. This would not be such an issue if you have an A2 upper.