This has been discussed recently fully in an Adobe Premiere Elements thread, using Horizontal Flip versus Time Stretch's Reverse Speed. Did you happen to read that?
From the clip you've linked to, it appears you want to reverse playback of your video.
There are a couple of ways to do this in Premiere Elements (including using the Time Remapping tool), but the easiest way is to simply right-click on the clip on your timeline and select Time Stretch. On the Time Stretch option panel, check the Reverse option.