Hello Anistus, Pierre
The latest AI starter installer, currently under test and available soon, installs very easily. It delivers an enhanced emulator, so a lot of the early App Testing can be performed on the PC itself.
Yes, Administrator is required to install programs on Windows PCs - same as any other program that is properly installed in accordance with MS requirements. Of course, outside of the class rooms and offices, most people are the Admin of their computer. Inside the class room and office, there should be an IT person that can distribute and install via the network........
Most Android devices have a bridging program (adb.exe) which will install with their PC interface software. You can also find third party bridging programs that, being dedicated to the task, can be easier to use and offer better functionality/performance. One such program is Syncios, which supports Android and iOS (App Inventor will support iOS in the future).