Display more than one stimulus at a time

Hi,

I would like to create a file where a video is shown in the center of the screen for 100 seconds. During these 100 seconds, other stimuli will show up to the left or right of the video, until the participant presses the left or right arrow key as appropriate. I'm having trouble finding out how to make the secondary stimuli show up while the first (video) stimulus is still playing.

Thanks for anyhelp!