What are blocks in Moodle?
Blocks are additional tools that can be added to the sidebars of your Moodle site. Their primary purpose is to provide important information quickly.
Several blocks automatically appear, including the Navigation and Administration blocks. Many more types of blocks can be added, including calendars and upcoming events. The following instructions will guide you through adding new blocks and customizing existing ones.
For additional information, see the documentation for Blocks on the Moodle site.
How do I add new blocks?
Navigate to your Moodle site and click on the Configuration Wheel on the top right corner of the page. Select Turn editing on.

Scroll down to the bottom of the left sidebar and click Add a Block.

In the pop-up window, select the block to add (Example: Calendar). You can only add one block at a time.

What do the icons on the blocks mean?
When editing is turned on, blocks have several icons in the upper right corner.

Move Calendar block allows you to move the block to a different location on the sidebar.
The Actions menu will provide some editing and configuration options for the block. There is also an option to change visibility to students and to delete the block.
I have additional questions - how do I get help?
For additional questions on editing Moodle courses, contact the Moodle team.