Go to Stepmania website.
Click on either Windows or Mac. (for catalina/big sur follow this link to download OUTFOX)
Install the software (run or save)
Click on the software Icon.
WINDOWS
If you get an error message - check it. If it mentions DLL file. Then follow this youtube link.
https://www.youtube.com/watch?time_continue=1&v=c5fxzdD3tZA&feature=emb_logo
MAC NOTE SKINS ERROR
note skins follow this thread
https://github.com/stepmania/stepmania/issues/1299
BIG SUR and STEPMANIA not Opening (OUTFOX)
Text instructions
Open applications
open Stepmania folder
Right click on Stepmania Icon
Click Show Package Contents
Click Open Contents
Click Open MacOS
Right Click on Stepmania UNIX executable and click open
Then just click behind the terminal page (don't close this window) when Stepmania opens
To make things easier
And load do the same process again
Right click on STEPMANIA UNIX and go to make alias, and put the alias file down on the right hand side of your tool bar or on your desktop
Then you can just click on that in future.