How do I login to my Interworx Control Panel (Linux) on my VPS ?

You can login to Interworx using:
https://MAINVPSIP:2443/nodeworx/ for example
https://201.11.777.9:2443/nodeworx

or

Once your domain has resolved:
https://DOMAIN:2443/nodeworx/ for example
https://myserver.com:2443/nodeworx/