Q: Transfer videos

Copy them from the camera roll to your computer. Add them to your iTunes library. Sync them to the device.

tt2

Depends on whether you are using a Mac or PC

In a PC - it goes to Pictures

In a Mac it goes to Photos

In iTunes - File -> import and then add them to the library

If you have stuff in a dropbox account - you will have to import them into the iTunes application first using the steps in this article

Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support

See Import photos and videos from your iPhone, iPad, or iPod touch - Apple Support. Photos and videos taken on an Apple device are not automatically synced to your computer, although that can be set up on a Mac. iCloud for Windows may be able to get most images and short videos via Photo Stream but longer videos will need copying via Windows Explorer. If the videos weren't taken on your device but arrived via email or some other route then then can probably be sent by email if they aren't in the exportable camera roll. Dropbox files can be copied as required.

Where you put them is up to you. I maintain a Pictures folder inside my iTunes Media folder (so it is all backed up together) and have a set of album folders in there for selecting to sync back to my device. If you want the videos to go to the videos app they will need adding to the iTunes library, presumably as Home Videos. You can do this by dropping copies or the originals into the Automatically Add to iTunes folder inside your media folder.

tt2