Once you know the engine size, you can:
* Consult your owner's manual: This is the most reliable source. It will have a diagram showing the spark plug location and the recommended procedure for changing them.
* Use a repair manual specific to your year and engine: Repair manuals (like Haynes or Chilton) provide detailed information and diagrams.
* Search online: Search for "[Your Aveo Year] [Your Engine Size] spark plug location" on YouTube or a car repair forum. You'll find videos or images showing the process.
General Information (but not precise): Generally, spark plugs are located on top of the engine, often under a plastic engine cover. You will likely need to remove the cover to access them. They're typically near the cylinder head.
Without knowing your specific Aveo's engine, I cannot give you a precise location. Providing the year and engine size will allow for a much more accurate answer.