After you have inserted a dart, you can easily snap the legs or the apex to various locations.
On the Main toolbar, click Select.
If editing the dart apex or a dart point, on the Horizontal contextual menu, ensure Edit Points is enabled.
Go to the Horizontal Contextual menu.
Select the Snap to option you want to use.
Note: When you edit an existing dart, the dart points and the apex can be snapped to the grid and to the guidelines.