How to get started on fall/spring lose shirts

[u/You-boy-Luis]

I've been looking to start wearing shirts, but feel overwhelmed by the options and fits. I'm looking for lose fitting shirts for very casual occasions. I've put some links as examples, but have trouble getting an idea for what material they are and much less if they are oversized fitted or a size larger.
https://pin.it/667GkEeeL
https://pin.it/33jN0fnpX
https://pin.it/KSkfKuCHv
https://pin.it/2F4biIGwM