What do I have to do to get Adobe to work on my iMac?

There is a large variety of Adobe apps and versions of those apps, so if the following doesn't help, you may want to reply with more information.

For the free Adobe Reader, click the top button at the right of the screen in https://get.adobe.com/reader/

The following may also be of interest: https://helpx.adobe.com/acrobat/kb/apple-silicon-m1-processor-support.html

Adobe is a corporation, not a specific app or program... If you want an Adobe app to work on your Mac, start by making sure the version of the app that you have is compatible with the version of macOS you are running...

Contact Adobe for support of their products.