"Would you drink green tea a few minutes after milk? (in the same
breakfast)

I read that milk prevents absorption of the good flavonoids in green tea.

If so, if you want both a cup of milk (with cereals) and a cup of green
tea
in the morning, what would be the right timing? Wait some time? How long?"

There was a study done on this question from which they concluded there is
no problem.  One study showed milk protein tends to clump with some of the
tea and in lab tests showed lower results for tea activity.  As I recall,
the other test measured the level of the tea activity in blood after
consuming milk and tea with no problem.  If still concerned, drink the
milk at the beginning of a meal and tea after, which allows milk proteins
to do the clumping thing in the absence of tea.