To Select a Keypoint Snap Point (with AccuSnap)

Select KeyPoint Snap mode.
With AccuSnap enabled, move the pointer over the required element.
AccuSnap displays the nearest keypoint snap.
If necessary, using the tentative hint as a guide, move the pointer towards the required snap point until the tentative snap point marker displays.
Enter a data point to accept the tentative snap point.

Selecting a Keypoint Snap point