This series is a collection of side stories for Legend of Galatic Heroes (1988).
They assumed thet you had watched the original series, and each arc was released out of the chronologic story order.
You don't to have watch the original series to enjoy these episodes though.
To help view them in order, each arc has been numbered with their chronological story order.
However, the arcs have been splits across 1998 and 1999 to reflect their original release schedule.
To view them in chronological story order you will need to jump between folders.

Ginga Eiyuu Densetsu Gaiden release order
Arc 2 - Valley of White Silver (4 Episodes)
Arc 6 - Morning's Dream Night's Song (4 Episodes)
Arc 9 - Disgrace (4 Episodes)
Arc 7 - One Hundred Billion Stars, One Hundren Billion Lights (12 Episodes)

Ginga Eiyuu Densetsu Gaiden (1999) release order
Arc 1 - Spiral Labyrinth (14 Episodes)
Arc 3 - Those Who Revolt (4 Episodes)
Arc 4 - Those Who Duel (4 Episodes)
Arc 5 - Those Who Recapture (4 Episodes)
Arc 8 - The Third Tiamat Battle (2 Episodes)