The live video interview is an opportunity for you to engage in a deeper exchange with recruiters and/or your future supervisor. This way you can learn more about the company and the position and get a better picture of what awaits you. Of course, you will also be asked questions - like at a job interview on site. The difference is that you are flexible as to where you want to conduct the interview.
Prepare yourself for the live video interview just as you would for an on-site interview.
All you need is a device with camera and microphone (computer, smartphone, tablet).
For technical information on doing live video interviews with the interview suite (e.g. which browser to use) see this article.