Can not drag user activity from backlog to canvas

I have been watching the videos and have created activities for the backlog from use cases. They appear in the backlog/reserve bar. I can click on them to return to the use case diagram, but there is no way to move them across to the user story map.

Also, sometimes when I go to the User Story Map or User Story List views, it isn’t even possible to edit the yellow Epic cards. However, if I navigate to it in some convoluted manner from Manage Epics and click on an Action Artifact that I created, I am able to edit the epics, but still not add User Activities.

Have a I missed a step in setting up the scrum. The whole this is not intuitive.

I am using a single license version of Professional v16.0.

May I know is your project using Scrum Canvas/LeSS process?