Leadtime by customer ranking

You need to indicate the order in which the values should appear.  Power BI has no concept of row numbers, you need to provide that manually.

Please provide sanitized sample data that fully covers your issue. I can only help you with meaningful sample data.
Please paste the data into a table in your post or use one of the file services like OneDrive or Google Drive. Screenshots of your source data are not useful.

https://community.powerbi.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-Forum/ba-p/963216
https://community.powerbi.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447523 

Dear Ibendlin,

Thanks for your advice,

I have the data with order date,ship date and customer ranking.

I need to no the order leadtime = ship date - order date and the chart of total order  ( item) by customer ranking.

Please refe the data on my link.

Thanks in advance and have a nice day !

 https://docs.google.com/spreadsheets/d/17b3dZlpPnvQH1f5hQ2-csU2SQLjc-9Be/edit?usp=sharing&ouid=103144787438833216419&rtpof=true&sd=true

Dear Ibendlin,

Thanks for your support and your DAX almost done with my expectation.But i still have same problem with the days don't have the data.Please refer attach file and i have explaint on that.

https://drive.google.com/file/d/1P0CaYIJSbI287zobbdEFqCewEhcehzxT/view?usp=sharing