In what format do I have the video files on external hard drive or USB stick to store them again later to view
What software do I need the DVD to the external disk or USB stick to get?
If it is (was at a family film it is) to not copy-protected material, the rich resources of the operating board, so in Windows Explorer. USB stick or removable disk connect DVD, double click on 'My Computer', then on the DVD drive, CTRL-A and then press CTRL-C, and then double-click on the USB Stick and CTRL-V. If the disc is full, you need a USB stick with more than 4 GB of memory - Removable likely more useful.
In what format do I have the video files on external hard drive or USB stick to store them again later to view
You need some program that can play DVDs. They can usually not only of disc, but DVD-synonymous data of hard drive to play. If you do not have:
Antwort von Quadruplex:

What software do I need icwas if it is protected?
Is unlikely. But if it were: the search engine of your trust. The use of such programs and the dissemination of instructions on how to circumvent copy of locks might be more obedient, thanks to the Ministry of Justice is now banned - so here you will find nothing about this.