There is the actual Open, with orders stacked up.
Then there is the Open first 3 minutes, with a lot of volume and noise.
Then there is the actual opening move, usually with a preamble.
Also there is often reports 30 minutes after the open.
Lastly a fair number of bots go off during this time because there is still volume and that often a key requirement.
I.e. a lot goes on but if you look carefully and study there are patterns, counter-patterns and reasons.
Hope that helps.