A time-stamped transcript is simply your transcript with times written into the text. Create time-stamps using minutes and seconds in brackets. Note that hours will be converted automatically into minutes. For example:

[05:12] This is a time-stamped transcript. These two sentences will be highlighted five minutes and 12 seconds into the video. [05:15] This sentence will be highlighted 5 minutes and 15 seconds into the video.

Once you have added in time-stamps, see the Import a Time-Stamped Transcript step-by-step guide to add the transcript to your Qmedia project.