Adding column values to provide a YTD total

I have an app where I record sales among other things.
I would like to keep track of Year To Date totals for each customer.
In my Sales Table in the YTD column under App Formula I have tried
SUM(Sales[Total])
When I click Test it shows me the total of all the Total column but it does not show anything in the App or in my spreadsheet.
I realize this should be a simple thing to do and I have searched the help articles but have not been able to find anything similar.

Well, I found out I had to add another sale to the App before it would show the YTD value in the App and the spreadsheet.
Except it does not show the newest sales total entry. Just the previous sales minus the current sale.
Is there any way around that?

You could add an additional piece to the SUM expression you are using, something like SUM(Sales[Total]) + [_THISROW].[Total]

Let me know if that works!

I tried your formula
SUM(Sales[Total]) + [_THISROW].[Total]
In the actual column and I deleted that column in the spreadsheet and added a virtual column
but it still doesn’t show a new entry.
As I only had test items I deleted all of the entries and when I did a new sale it came up as zero in the YTD column.

I tried your formula
SUM(Sales[Total]) + [_THISROW].[Total]
In the actual column and I deleted that column in the spreadsheet and added a virtual column
but it still doesn’t show a new entry.
As I only had test items I deleted all of the entries and when I did a new sale it came up as zero in the YTD column.