In every note there are some buttons on the upper left.  One of them is a circled dot.   That takes you to the thread view.  This shows that note in context of a thread, with it's replies and ancestors.  The equals symbol is a menu of things, each with a popup submenu.   The eye, when hovered, shows the relays that the event was downloaded from.

There are buttons at the bottom of events too.  The chat bubble lets you reply.  The refresh arrow lets you repost.  The ellipsis lets you quote.  The lightning bolt lets you zap a lightning payment to the author.  And the heart lets you react with an emoji.