Okay, I mentioned putting feeds in folders already because each time you add a feed, Inoreader prompts you to put that feed in a folder. It's okay if you don't do that right away, though, because you can add feeds to folders any time.
Feed-and-Folder Panel. You'll see all your folders in the left-hand navigation panel, along with feeds that are not in folders (yet). You can drag and drop to rearrange items in the navigation, and you can also drag and drop feeds into folders. (You cannot put folders within folders though.) When you click on a folder title, you will see all the contents of all the feeds in that folder on the right. When you pop open a folder, you will see all feeds in that folder and can click on those individually, see the contents of each specific feed to the right.
Student Feeds / Class Folders. The way I run my blog network is that I subscribe to each student's blog feed, and then I put those feeds in class folders: I have one folder for each class, plus a folder for all classes. That means each student's blog feed is found in two folders: in a specific class folder, and in the all-classes folder. This allows me to look at incoming content in three different ways: by student, by class, and by all-classes. I don't organize the students alphabetically inside the folders because I can just use Control-F to find the student I need:
Folder Options. Just like with a feed, you can click on the down arrow next to the Folder name in the top navigation menu and see various folder options. One of those options is an email delivery service! I'm just trying that out for the first time now. (I think this is a premium feature, not available for the free accounts.)
Preferences: Folders. You can manage folders in a different way through the preferences panel, which you access through the upper-right-hand corner avatar link to your account, like this:
This Preferences view is also a way that you can check for feeds "without folders" if you want to make sure you have all feeds in at least one folder (that's my organizational strategy).
So, that's all I can think of to say about folders, but you can let me know if you have any questions... next up: Inoreader Tags.