Assign an automatic transitions to a slide for MS PowerPoint

• View or select the slide in Normal or Slide view. 
• On the transition tab,  in the Transition to This Slide group,  check the After : check box, 
• In the Automatically After: text box,  type a transition time,  in seconds, to replace the default time 
• To apply this setting to all slides in the presentation,  click Apply to All icon. 

Note : You can leave the On Mouse Click check box selected even if you choose automatic transitions because there may be times when you want to manually advance to the next slide before the automatic transitions time has elapsed.