Here are some pictures of when I did mine a while back:
The thermostat is in the lower left:
Thermostat removed:
Old thermostat:
Close-up of new one put on:
The clamps are a pain in the ass to deal with, so do not let them come off the hoses if you are reusing them. Make sure you keep a close eye on your temperature gauge and check your coolant levels for the next few days after putting the new one on. Also, this is a good time to flush your coolant if it is due.
Link to the metal one I bought: Dorman Thermostat Housing Upgraded Design Metal for Aveo 5 Lanos Wave 1 6L | eBay