The turbine is basically a rotating fan that extracts the energy from the hot gas flow which are expanding rapidly to rotate the compressors and sometimes other accessories.
The basic engine must have 4 elements:
Suck -> Squeeze -> Bang -> Blow.
meaning
Air Intake -> Compression -> Ignition / Combustion -> Exhaust
the Turbine operates within the combustion chamber section.
Hope this helps.
*EDITED*
There are different types of turbines,
-Single Stage
-Tripple Stage
-Free power contra-rotating turbine,
but they all operate in the same principle.