How to navigate in the slide

Hi i d like to be able to see my slide at a certain timing to add my button correctly

ex: i want to add a button at 2mn in my slide. I d like to be able to see the slide at 2mn to position the button perfectly. 

It seems i can add the button at a certain time but as i can t see the slide and all its component at 2mn (different than the at 1 second) i can t position perfectly my button

thanks for your help