If you requested to download the Community Edition you get the .exe installer. Right click on UiPathStudioSetup and you will see the extension as well:
Now, second thing, you cannot manually activate Community Edition. It’s stated in CE terms and conditions and it’s one of it’s limitations.
You can read details here:
If you still encounter errors with online activation, you should try to see if you’re behind a firewall, or if antivirus is blocking the installation, etc.