The autotrace version? get the installer https://github.com/autotrace/autotrace/releases and install.
Copy autotrace.exe and libffi-6.dll into C:\Program Files\GIMP 2\bin (the other files already exist in Gimp)
plugin-trace.py goes in your user plug-ins folder Registers in Filters -> Edge Detect -> Trace
Some screenshots: https://i.imgur.com/Pyw6Us2.jpg
Edit: Just had a look at the download from your reference. I still use version 0.4 plugin-trace.py attached in case you need it.
Copy autotrace.exe and libffi-6.dll into C:\Program Files\GIMP 2\bin (the other files already exist in Gimp)
plugin-trace.py goes in your user plug-ins folder Registers in Filters -> Edge Detect -> Trace
Some screenshots: https://i.imgur.com/Pyw6Us2.jpg
Edit: Just had a look at the download from your reference. I still use version 0.4 plugin-trace.py attached in case you need it.