List the items in your dataset in chronological order and provide suitable headlines to match the amount of items. If you for instance have 10 items per year, it does not make much sense to part these 10 items into months. If you have 100 items a year, but also have months without any items, it might not make sense to list all months.
Either you can provide links to pages that shows all items per time period, or simply make a list of links to each item directly on the main archive page.
Use the archive pattern when it makes sense to list items in chronological order. List items in an archive format, makes it easy for the user to explore how the website of interest has evolved over time and what has influenced today’s items.