How to get Maven?

Anyone can explain how i can get Maven to spawn?

So i was unlocking my atlas and got the Maven in one of my lower lv map, in a tier 3 Arcane map. I have her icon on this map. But since i was unlocking the atlas, i just ignored her, and didn't do her map. Fast forward, i drop my first red maps, so i want to come back to unlock Maven. But then no matter what tier Arcane, and the number of watchstone i put in the region, she just don't spawn anymore.

Anyone know the mechanism behind, is there something special i have to follow or do to get her?

I think You should press button to become orange this button is above masters missions...
After fulfil bar of ascendance She will drop Maven Fragment . This fragment is used in Map Device to open Maven fight . all bosses from previous map will fight with You.

Try to run more maps in that region where you already have her icon on your map, because that region should be of interest to her. On the map device check that you have enabled the Maven button when you run the maps. This should 'collect' the bosses of the maps when you kill them. When you have filled up the boss-fight bar in that region, you have collected enough bosses and you should receive a invitation for the Maven arena boss fight to fight them all at once again.

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