Select Two Topics
Before create relation between 2 topics, you need to select these 2 topics at first.
These 2 topics must one is parent and one is child topic.
Click "MindMap" tab -> "Add Topics" group -> "Above" button, to add a label above of the connector. It is a relationship for these 2 topics.
You can edit the label to descript relationship or flow direction between these 2 topics.