These icons will sort the posts by Best, Hot, New, Top, or Rising if you’re logged in. You can sort these posts by clicking one of the icons on the ribbon menu located underneath the Create Post text box (if you’re logged in with a Reddit account) or under a smaller header called Popular Posts if you’re not logged in.
The homepage (or “front page”) shows you various posts that are currently trending on the site, pulled from a variety of subreddits.
If you’re just looking at Reddit for the first time, you may be a bit confused by what you are seeing, so here’s a quick rundown.