create a slide that has a set space for inserting a video.
two ways:
1 - to place individual video with different sizes on different slides:
drag the video file onto the slide then resize and position as needed
2 - use a placeholder to set the video the the same size and position on any slide:
open slide master (view > edit master slide)
place a video file on the master slide then size and position on the slide (any video in the format ratio you want to use can be used, the video itself will not be used its only to set the placeholder position)
Format > advanced > define as media place holder
close master slide
to use; drag a video file on to the video place holder
insert that video and have bullet points appear at set times to parts of the video
click on the text tool button on the tool bar (T)
enter the required text and position anywhere on the slide
select the text box and format as a bulleted list (inspector > text > bullets)
save those 2 components as a video that can be played in unison.
File > export > QuickTime