Refer to figure.
A gas turbine engine is basically a heat engine using air as a fluid to produce thrust. The working principle of the gas turbine engine is comparable to that of a piston engine as both engines use a cycle made of induction, compression, combustion, and exhaust phases.

In a piston engine, the otto cycle occurs, with a stroke of the piston doing each job, induction, then compression, then combustion, then exhaust, and you could have 2, 4, or even up to 16 cylinders all doing their own cycles at slightly different timings to even out the power production. This reciprocating motion is then turned into rotation by the crankshaft and connecting rods. The ideal otto cycle has the fuel/air mixture combust at constant volume, and the temperature and pressure both rise to provide the cylinder's power stroke. Diesel engines, due to the difference in combustion type from ignition combustion to pressure combustion, do have a different "diesel cycle" which assumes constant volume combustion, but this hasn't reached the learning objectives yet.

In a turbine engine, the Brayton cycle runs all 4 parts of the cycle, but all at the same time in different parts of the engine, and therefore is much smoother and more efficient for aviation operations. In general for modern turbojet and turbofan engines, the process is axial, so the air runs from front to back and the engine components spin around a single central axis. Another difference from piston engines is that turbines combust fuel/air at a constant pressure, with the temperature and volume of the air increasing.

Summary:
Piston engine
-Process is intermittent.
-Combustion occurs at a constant volume.

Jet engine
-Process is continuous.
-Combustion occurs at a constant pressure.