follow the step:
1. Switch to edit and select design option then from menu select WIDGETS and click on "content block" option. SEE image 1
2. A black box will appear which will define the content boundary. On top side of that black box you will see edit option. when you will click on edit option you will see a explorer(see image 2).
3. In the explorer go to the content folder >> the "department" folder where you have created all content or want to create a content. Select option "new" to create new content block or otherwise select the content file and click save option.
4. After this click on check in or publish to view changes.