Which sheet are you trying to join?
It's much harder to help you without the actual data so if there's any way you can attach the actual data to this post it would be better.
Thanks for the replies so far.
By looking at your replies, the problem isn't the dragging of sheets into the data pane. I understand that under the Sheets there is *Metadata, *SUBSET and *TOTAL. All of these join no problem.
The main problem is that the Carbon-emmisions-borough excel sheet (as seen below) does not turn up under the 'sheets' heading.
Whereas, in the video, the carbon-emmissions-borough excel worksheet turns up under 'sheets' no problem. See below:
The excel worksheet: https://mkt.tableau.com/Public/Datasets/carbon-emissions-borough.xlsx
So, under sheets I have *Metadata, *SUBSET and *TOTAL. But I have no 'carbon-emissions-borough', as you can see by the video screenshot above. I have compared 'SUBSET' and 'TOTAL' with the 'carbon-emissions-borough' sheet and the data is not the same. For the sake of doing things correctly, I would like to follow what the video is doing, with the same data.
So I guess my revised question is: Why isn't the 'carbon-emissions-borough' worksheet under the Sheets heading in my workbook? Could it be connection/joining settings that I have not configured?
Again, many thanks for responses so far.