How do you Add Leader when using GstarCAD?

Add Leader: Adds a leader line to an existing multileader object. The new leader line is added to the left or right of the selected multileader, depending on the location of the cursor. You can perform this option by selecting add leader icon located in the leader panel.After select this option, a prompt message will display > Select a multileader:For example, selected the Mleader which contents the block D. Then specify the leader arrowhead location.