Connect laptop with projector?

I just have the problem that I have connected my laptop and my biemer via hdmi, but only my home screen from the laptop is displayed. I wanted in netflix and in the suffering you can see that it is open but the app itself is not displayed (on the laptop it is). This is the case with every program. What can I do?

Times press Windows key and P and adjust the output. This may fix your problem.

Windows + P and then on Duplicate. Then it should work.