How do I install Python 3.8 on Windows 10 and use it in the Powershell?

I'm clumsily clinging to the Python installation on my laptop. I've already installed Python on a variety of PCs, and so far I've had to reboot to use my Python scripts on the command line.
If I enter python in the command line now, this Appstore from Microsoft opens and wants me to download Python, although I already furnished the newest installation… Do I have to do something besides the PATH variable?

OS: Windows 10 Home

The Python installer should have a checkmark to automatically add it to the PATH.

But yes, Python also needs to be in the path to be able to call it directly from anywhere. Otherwise you have to call it with the complete path

I chose that!

It works the entire path.