Save the new PDF as a file named with just the edition number, e.g. 217.pdf.
Find the page containing the Harwell News and open for editing.
There is a table with a row for each year. Each row has the year number and a separate Document Gallery to hold the six issues for each year.
Select the Document Gallery and open for editing.
Add to Dcoument Gallery (top left).
Drag the new edition into the Media Library and select it.
Add to Document Gallery (bottom right)
If needed adjust sequence in the gallery.
Select the new edition, and edit the attachment details, bottom right.
Title should default to the edition number, e.g. 217 (from the filename).
Add a Description of the month and year, e.g. Aug 2019
Update Document Gallery
Chcck the results.
Note: Each year a new row and a new document gallery is needed.
2020 will start a new decade, so the existing post for 2010-2019 will need renaming, and a new post opened for a new decade. Menus will also need adjusting.