You could click the link i already provided above. (tip: the view menu holds the key) Here again the same link (This time with the full title): Pcb_new: What is a canvas? (default [legacy], open-gl [accelerated] and cairo [fallback]) Is there a difference?
But open gl does not have the global spread and distribute function.
So again: stay in default (now legacy) canvas. activate the footprint mode (top toolbar somewhere on the right)
left click somewhere on the canvas. In the context menu that opens open the submenu for “global spread and place”->“spread out all footprints”. (If that entry is not in the context menu toggle the footprint mode button and try again)
More details (including screenshots) see relevant section of the kicad docu: http://docs.kicad.org/4.0.7/en/pcbnew.html#_automatic_footprint_distribution