Who act First

[Olliande]

I am curently reading the Hero system volume 2 and i'm a little confused:
Who act first:
John DEX 19 and Bob Dex 20, does Bob act first like in the 5th edition or is there a dex roll to know who act first?

Or the dex roll is for the same dex only?

[Steve Long]

6E2 16 clearly describes the standard order of combat, where characters who have a Phase in a Segment act in order of their DEX. There are rules for resolving any potential conflicts in these situations on 6E2 19, but those are only for use in unusual situations.