I think the issue is because with feature linked annotation, the piece of anno should be coming from the line feature class first. Not the annotation feature class first. Try this workflow instead:
1. When you create the new line feature class, add a field called Name then follow the same workflow as you have in the video.
2. In the LINES layer, create a new line and in the Attribute pane, type a value for the Name attribute field.
3. In both the LINES layer and the LINES_ANNO layer, you'll see the attribute value. In the Name field for the LINES layer and the Text String Field in the LINES_ANNO layer.