You can add a span & versine annotation by following the simple steps below.
Step 1: Navigate to the ‘Annotations’ section of the Lineardraft toolbar
Step 2: Click the 'Add' button
Step 3: Click on the start and end structure of the span
Selecting the two structures will prompt the span annotation to appear.
You can click on additional structures to add annotations to multiple spans. Right-click when you are done to stop adding.