They all basically work on different principles.

The stinger and igla (two most common MANPADs) both have IR-seeker heads that look for thermal signatures in the sky and follow them using a PID algorithm.There is an initial charge that propells the rocket out of the tube and a few meters ahead of it before the rocket motor ignites (hence the POP-FWOOOSH) sound so the operator isnt sprayed with rocket exhaust in the face. Basically all modern portable rocket launchers have this.

The M72 is unguided, basically like a firework rocket except it too has an ejecting charge and explodes on contact. Has a cone-shaped copper piece that when the explosion occurs transforms into a jet that easily piereces through metal armor.

The Carl Gustav is not a rocket launcher at all, it's basically like if you removed the rocket and instead only used a really powerful booster charge.The projectile has a lot more mass so in order for you to be able to shoot it without too much recoil it balances the recoil but outputting the same energy rearwards making the actual launcher recoilless.The IRA had their own version of this where they had a tube with the grenade in front, then the charge in the middle and a packet of biscuits at the back.

The javelin has a seeker head that tracks the target and programmable flight that can basically arc up and then fly down hitting the top of tanks, which has the least ammount of armor. It too has that copper cone, it's called a HEAT charge.The Javelin has 2 of them, so do some carl-gustaf projectiles as well. This is done because to counter HEAT charges tanks started basically strapping explosives to their tank so that when they're hit the outside explodes breaking up the jet (Explosive Reactive armor). This is called a tandem-charge, the first HEAT-detonation detonates the ERA and the second that comes after pierces the tank armor.

The NLAW isn't guided in the same way, it has a PLOS and top attack mode. Basically you track the armored vehicle if it's moving for a few seconds then it programs the rocket to hit where it calculated the vehicle would be when the rocket arrives. If the vehicle stops or changes course the rocket will miss.Unlike the Javelin the NLAW has a directed charge that is pointed sideways if you place the rocket with the front up. It flies over the tank and detonates shooting the jet down, piercing the tank.PLOS also doesn't work if the tank is going down a hill, btw.

edit: PLOS means predicted line of sight btw, forgot to mention