I get lots of warnings on my Mac when I am trying to download Soundflower. What has gone wrong?

Soundflower is an old app and as far as I know has not been updated for Monterey or Apple Silicon.

I suggest considering Soundsource or Loopback, which you would have to purchase. BlackHole Audio is similar to Soundflower and has been suggested by a number of users in these communities.

in addition to the good answers that you've received, soundflower started being difficult to install on Catalina. then it became even more difficult to install when Big Sur was introduced. I also used to use soundflower, (since Catalina) but had to abandon it in favour of BlackHole because it was easily installed on Big Sur. and I couldn't in good faith recommend BlackHole unless I used it myself.

Possibly it is old and doesn't conform to the new kernel extension requirements. The last reference to it I've seen in user reports is it was made for Snow Leopard. While if written correctly then, it certainly could have continued to work with macOS all the way to about Catalina or Big Sur. It was about then that Apple required a new method to inject kernel extensions.

But, if you post the warnings you get, we might not have to guess at why you are getting warnings.