Installing multiple versions of Content Station can be done on Mac OS (not on Windows):
Step 1. Install the first instance of Content Station.
Step 2. Rename the installed file, for instance by adding the version number.
Step 3. Compress the file to turn it into a .ZIP file.
Step 4. Install the other instance of Content Station.
Step 5. (Optional) Rename this file as needed.
Step 6. Unzip the file which was compressed in Step 3.