The "Private WS " column shows the private memory usage of a process. This is the same as the "Memory (private working set)" column shown by default in Task Manager. This is not the full memory usage of a process. The "Working set" column will show more but due to process memory sharing there will be some double counting. Memory usage in any modern OS is complicated.
"Private bytes" is the same as the "Commit size" in Task Manager. Unfortunately this is a difficult concept and not easily explained or understood. You really need to understand how a modern virtual memory operating system works and that is not simple. I don't know of any explanations on the Internet that are accurate and easily understood. Most explanations I have seen tend toward being easily understood at the expense of technical accuracy. Many are more wrong than right.