There are manga and light novels in Sword art online with three simultaneous separate series. What is the way to chronologically read this series?
The manga is just an adaptation of the Light Novels, so it follows the arcs in the original LN.
- Fairy Dance
- Phantom Bullet
- Mother's Rosario
The Girl Ops manga can be read at any point after the Fairy Dance arc, as it's just a side-story.
Progressive is a reboot of sorts of the Aincrad arc, exploring from the first floor onwards, so it can be read on its own whenever you want.