Luis Perez answers many initial questions about how the new MacBook Pro's Touch Bar works with VoiceOver. Luis describes the new Touch Bar, then shares his experiences of using the Touch Bar with VoiceOver. Luis shared, "The real power of the Touch Bar lies in the fact that it can morph into a variety of controls, depending on the app that is open."
Basic Touch Bar VoiceOver commands
Simply run your finger over the Touch Bar or using the flick right/left gesture and VoiceOver will announce the items. With the VoiceOver focus on the desired item, double tap or split tap to activate the item. Due to limited vertical space, there is a new command to adjust a slider (such as brightness); to adjust a slider, double-tap and hold followed by sliding your finger right or left.
For more information, read his article, VoiceOver on New MacBook Pro with Touch Bar: First Impressions.