I created a SharePoint online list called CustomerList with a column called CustomerID which should be the value of ID plus 5000 so CustomerID in the first image would be 5001, 5002, 5003, 5004.

I followed instructions here, here and here but my ‘Increment variable’ is asking for a value but not allowing me to select it, it appears as a grey rectangle. I also checked stackoverflow for a similar question but did not find one (unless I accidentally overlooked it).

Does anyone have any suggestions as to what I did wrong in my flow?
Thanks