Selecting the presentation button will launch your deck as a slideshow in a new tab. This will start from the current slide.
Use the arrow controls in the bottom right of the screen or swipe on a touch screen device to move through a presentation.
left / right arrow key = move forward / backwards through slides
f = full screen mode (ESC to exit)
o or ESC = show / exit overview of slides
. or b = turn screen black / return to slides
s = launch speaker view in new browser window, showing current and next slide, notes and timer.