This sequence diagram demonstrates how to insert a note on the right, on the left, and over the actors.
Notes template code in Gleek
// Left note
This is a note on left:note <-- Bob // Right note Another note on right:note --> John
// Over note
Note over actors:note — Sam
Note over actors — Emily
About sequence diagrams
Sequence or event diagrams help create an overview of how a system works. Sequence diagrams show how all the different parts interact with each other over time, carry out the required actions, and complete processes. A sequence diagram descends from top to bottom showing a sequence of interactions and sequence diagram notations.