See The Diagram Mode Toolbar

Click an area for help

The Right click menu provides quick access to common functions

Shortcuts        

You can move single symbols or groups with the cursor keys. Hold down shift and a cursor key to move the objects in larger steps.

Note - presss Escape to hide the symbol controls first

With a single object hold down Ctrl and a cursor key to change the size of the object.

You can swap two symbols by dragging one onto another.

If the symbols are of a different class, start dragging then hold down shift before dropping.