Resource types and uses
There are several types of resources - the ones that will be the most useful to you are file, folder, label, page, and URL. To add a new resource, turn editing on by clicking on the button, Turn editing on, found at the top right of the page underneath your name and profile picture. Click on the grid topic you would like to add a resource to, a pop up window will open, click on Add a resource..., and select the type of resource you would like to add.
File: Upload and link to a file (I strongly suggest that if students don't need to edit this file that it is in PDF form)
Folder: Creates a folder for adding files to (The advantage of this is that you can add or remove files from this folder and the step of linking them individually is unnecessary. Uploading ZIP files to avoid multiple uploads is highly recommended)
Label: Insert a label between resources to assist users navigation
Page: (compose a web page)
URL: Link to an external webpage ((it could also be used to link to another course on the site if you are team teaching with another teacher)