The uses of the noble gases come directly from their properties. The three that matter are inertness, low density and non-flammability.
Helium has a very low density, much lower than air, so a balloon filled with helium floats upwards. Helium is also non-flammable. Hydrogen has an even lower density but it is flammable and can explode, so helium is the safe choice for party balloons and airships.
Argon is inert. Inside a filament lamp it surrounds the very hot tungsten filament. Because argon does not react, the filament does not burn away as it would in air. Argon is used in the same way in welding, where a stream of argon around the hot metal stops it reacting with oxygen in the air.