After the video has been loaded into the software the steps below will allow you to rotate the video as you need.
1. Click on the Edit button on the right side of the file thumbnail.
2. Go to the Adjust tab and use one of the four options to do the rotation that you need. You can rotate the file as follows: Rotate 90 degrees Left, Rotate 90 degrees Right, Flip Horizontally, and Flip Vertically. Clicking on the icon will do the rotation for you, and you will see the rotation in the preview window. After you have your desired rotation complete, close the window to save the settings.
This video guide will assist further: http://youtu.be/JJ_7RrhOUdw
Tip: The changes will be saved once you complete the conversion of the video. Choose the Output Format that you wish to save the file in, and then click the Convert button.