What version of Premiere Elements are you using and on what computer operating system is it running?
In the absence of that information, I will generalize for now and customize the reply to what you are asking when you give the above information.
Assuming you are using Premiere Elements 11, 12/12.1, or 13/13.1 on Windows 7, 8, or 8.1 64 bit...
To rotate your video
a. right click it on the Timeline and select either Rotate 90 Right or Rotate 90 Left
b. select/highlight the Timeline clip, go to Expert workspace's Applied Effects Tab/Applied Effects Palette/Motion Panel expanded...in the middle of the Motion Panel expanded is a Rotation feature with more options than the Rotate options at the Timeline level.
Please review and consider, and supply more information.
Any questions or need clarification, please do not hesitate to ask. With the details, we can customize a direct reply.