@Shrap, I can at least help you with the first 2 things
To quote someone, well first off, copy whatever you want to quote, paste it and then press the button with ” (next to the slanted i), then to get out of quote mode just
Like this, with the space inbetween lines, and press the ” button again
@, I @ed you, so now when you click on @ you, which will appear in green, it’ll bring you straight to your profile, there’s probably also a way to get notifications if someone @s you