A Task Link is a special type of Visio shape known as a dynamic connector. Visio allows you to select a dynamic connector shape and use it to automatically link other shapes on a page.
To turn the Task Link into the active dynamic connector, click on Visio’s Connector Tool (see step 1 in the diagram below) then click immediately on the Task Link shape in the TaskMap stencil (see step 2).
Though the cursor is not visible in the picture above, on your screen you will see that the cursor now includes an attachment that looks like a Task Link.
When you click and drag between any two connection points, Visio will drop a Task Link into place.
The Task Link will remain attached to the Connector Tool until you click the Pointer Tool (the button with the arrow to the left of the Connector Tool).