Can someone explain to me how CAO works?

I’m from Poland, but currently living in the US (exchange) and want to apply to Ireland. I’ve watched a video of a woman showing a demo on youtube and she said that you don’t need to submit any personal statement or anything - just your information and preferred courses. I will be applying to TCD is that changes anything. What I was wondering is when do I send my test results - SAT, APs, Duolingo English and my Personal Statement?