This will be helpful to those who can not run PowerShell for some reason. First, run the Bizhawk prerequisite found here. Yes, this step is absolutely required.
Next, download the following zip file and extract it to its own folder. This will contain an archived version of the co-op build from 12/27/18. https://www.dropbox.com/s/t9ia81ao993rhtv/BizHawk-2.3.zip?dl=0
This archival copy will need to be updated a bit; you will need to download the latest build of co-op and replace the ram controller files in /bizhawk-co-op/ramcontroller/. The latest version of this file can be found at https://github.com/TestRunnerSRL/bizhawk-co-op/tree/master/bizhawk-co-op/ramcontroller.