Prolly recommended to put the barrel in a vice clamp to remove the flash hider as they can be tight!
My front sight came right off easy, almost too easy! With the gas tube! And my barrel nut was loose! Thus the first recco!
Gotta pull the handguard retaining plate, whatever you call it, trash it and go for the rest. Most free floats come with a barrel nut, so you gotta set up for that.
Then you gotta deal with the issues of FS and gas block alignment upon re-assembly. As there will no longer be a plate there, and you want the front rail to line up with the rear, you gotta do the math!
Not sure just how critical the gas port alignment is with a .030 or so part missing, as they are designed oversize as compared to barrel, yet a possible factor.
Alignment is the other issue in a rotational sense, I just put my upper on a flat glass table to level front and rear rails before tightening so they are level.
My gun had issues from the start and my gas port measured .068 . I enlarged to .073 and it has run fine with all ammo since. Just FYI!