On a Calendar View Entities are represented as events on a monthly calendar:
To be honest, Calendar View is not yet fully done, so it is very limited and not user friendly:
To add a new Card, click … on the top right corner and select Add New option.
To edit planned dates you should navigate to an Entity, there is no drag’n’drop support yet.
Not yet planned Entities are not visible, so you should use an alternative View to set the initial dates.