SaaS Sequential numbered Customer Numbers

I am following the old instructions for this from this thread: Auto Numbering - Customer ID
However it appears that this was written around version 10.x and while some of it is working, and I found references in here to adjust the Ice.Lib.NextValue function call, now I am getting an error that “ttCustomer” does not exist.

I do have some minor programming background, just not in C# and I am pretty new to Kinetic. I did kludge my way around the information in the PDF “How to Auto Assign Customer E10 using ICE Next number.pdf”.

I am betting this is fairly out of date and there is likely an easy way to refference the customer without using the temporary table, but could use a little help from the group please and thank you.