Steps
Select Projects>Document>My Documents>plus sign on right corner>import
Choose import from option from where you want to import Diagram
Use imported diagrams as templates for new creations
Trace over imported shapes to create editable versions
Combine multiple imports on one board
IF you want to import any Selected file from your computer on board then Click "Upload" from sidebar menu to add the file to your canvas.
The imported file image appears on the canvas as a single element
Resize and reposition as needed
Delete or hide imported elements once you've used them
Notes
PDF imports add multi-page support (one page per import)
Large images may need to be resized for optimal performance
Imported images can be converted to traceable templates