When you record segments of your event, you can also trim them so you can add a specific section of the recording to your Replay tab.
To do this, you need to head over to your recordings in Event Dashboard > Recordings and find the recording that you would like to edit. Click on the recording to open it up. 
Once opened, you will have the option to Download, Trim, or Delete. Click on the small scissor icon to open up the video editor.
A pop-up will appear where you can begin trimming your recording. You can click and drag each end of the blue bar to adjust the start and end time of your recording. Alternatively, you can use the small arrows to increase or decrease these times in two second increments. Once you're done editing the recording, hit Save.
Another pop-up will appear explaining that it may take some time for the changes to be applied, and that you can revert back to original video at any time. Hit Save again.
While your video is processing, you won't be able to trim or download your video. You will see a note on your video saying that it is processing your changes. 
Once it has been processed, you can choose to publish the recording for attendees to view in the Replay tab of your event.
You can choose to Download the recording or Trim it again. If you choose to trim it again, you will see a pop-up asking you to restore the original recording. If you click Revert then the trimmed version will no longer be available to view in the Replay tab.
This will then open up the trimming page for you to edit the original video once again. You can trim and download different versions of your recordings as many times as you please, however you cannot publish more than one version at a time.