I have my ETA for Australia. Now what? Is there something I m suppose to print out?

You don't print out anything for your electronic travel authorization. When checking in for your flight with your passport & boarding pass, your ETA shows up on the airline's computer. Likewise, when you arrive & go through immigration, present your passport & your ETA shows up on their computer. It's all electronic. Save a tree & go paperless.

Your ETA is attached electronically to your passport and is accessible by all airlines that fly to Australia and Australian immigration when you land here. You don't need to print anything ; all you need is the passport you nominated when you applied for the ETA. Australia has had electronic visas for many years now and they work well.