How to install PREY on an Note Ultra 20

I can navigate app well and its easy to find where to add a device. When I click on add device, it asks me to scan a QR code and it pulls up just fine. Now what do I with the QR code and how can it help me install Prey on my Galaxy Note 20 Ultra. I have read Fabian’s instructions on installing on Android; however the settings on the Note 20 Ultra do not match the instructions…has been a good way to learn about my new phone. Previously had an Galaxy S5 and prey installed easily. I have tried uninstalling and reinstalling, clearing cache. Nothing works. One of the biggest headaches is trying to find the administration permissions. Your assistance in getting PREY installed would be sincerely appreciated