Help with simple waterfall chart

Thanks - There's only one table I'm using, does that matter? 

For now I've simply put visual cards at either side of my waterfall chart to show the before and after values of the numeric value that is changing over time. It's not great but it'll do. I'll have a proper read of the tutorial you sent over, I'm sure there's a way to do that in PowerBI automaitcally, but oddly it doesn't give any option for me to do it in the list of possible fields in the visual