Update File Date/Time allows you to modify Date Created, Date Modified, Date Last Accessed. This doesn't change the filename itself, this changes the file system dates on the files. A typical example might be if you took some photos with your digital camera, then copied them to your computer, sometimes the Date Created is changed on the file to the date that you copied the file to your computer, not the date you took the photo. So, you can use this section to set the Date Created to whatever date you took the photos.

Use Current Date / Time

When this is checked, it overrides the manual Date / Time entry and automatically uses the current Date / Time.