[JasonB]

There are several ways to do it.

If you're on the Recent Posts, or New Posts page, you should see a little green arrow next to the thread title. This will take you to the first new post in the thread.

More generally you can jump to the last post in a thread by clicking on the little arrow icon in the Last Post column, over on the right.

Or, for me on Windows 10, the first and last pages in a long thread are always shown. So for instance the page numbers in the painting figures thread go 1, 2, 3, 4, 5, ... 15   if I'm at the start of the thread, or 1, ... 11, 12, 13 ,14, 15 if I'm on the last page.