You can add a custom block on Basic Pages by following the same steps as creating a Sidebar type of content, with a few extras.
- Add Content of type Custom Block.
- Enter content in the Body section.
- You should find an option called: Content Block Style with the following options: Buff Top/Bottom Line, Gray Bordered Transparent Background, Gray Bordered Gray Background.
- In the Related Content section, type in the node number or page title (autocompletes).
- Save and publish.
- Your custom block should now appear on the destination Basic Page.