What exactly do you call those grenades launched from the rifle? Is there a special way to fire them or do you just shoot it like a normal gun? Any good links?

Good link. Looks like you should place the butt against something solid to fire it. Not eant to be fired from the shoulder like a normal bullet

no these weren't these were almost like a mortar at the ready and quik movement they were designed for fire and move tactics especialy long range targets. they were very handy.
theres on scene in saving private ryhan that one is used right off the beach when there on top of the sea wall one is fired into a naval gun post that was occupied. check it out. hope this helpd.
Graeme