When I use the
Export frames to PDF, I cannot find the way to order the frames as wanted. They seem to be exported in the order they were created. Any idea on how to change that?
I am sorry I did not get what exactly you are asking, but within the PDF file, each frame will be on its own page, ordered according to its position in Figma, from top-left working down to bottom right.
You can select all the artboards with having a numerical order i.e. 1, 2, 3 and so on, and export it to pdf in a specified selected folder/ separate new folder. And then merge them/ combine them.
There are many online websites that allow you to merge pdf easily. You can use this one too to do the same.
Please see the screenshot below
Then merge it