Are there specific topics that I need to study for the DET test?

Place your phone on your side (left or right). Slightly behind you. Do not place it directly in front or to side where it cannot see the screen. It must be in Landscape mode (horizontal).

Yes! After room scan you may be asked to perform an ear scan. You will need to keep your phone camera close to you. This proves you are not wearing wireless earbuds. 

Yes, many Belgian universities now take the Duolingo English Test. It is much more easy and cheap than IELTS. Schools like University of Antwerp or VUB often accept it, but always check their website first.

No, you can not. You must use a laptop or desktop computer. Make sure it's OS is Windows or macOS. iPads, tablets, and Chromebooks are not supported. Because they cannot run the secure test launcher software. 

Yes, other than IELTS or TOEFL, the Duolingo DET test is also valid for the University of Liverpool admissions. 

Although international students should have a minimum score of more than 100 to get admission here.