We've added new Tips and Samples for working with table data in kintone.
The article in the Tips will give you a detailed run-through on how to utilize table data. The article in the Samples will give you a quick copy-and-paste code that you can quickly use.
Tips - Count table rows
https://developer.kintone.io/hc/en-us/articles/115003487808
Samples - Utilizing Table Data