How do I remove contact duplicates using web browser on windows

I access iCloud in my Windows machine using a web browser. I've imported contacts using the Import from vCard feature and ended up with duplicates. I'd like to merge duplicates, but I can't find any dialogue from the web browser interface to do this. And when I search for help online, I've failed to find anmything abotu accessing iCloud contacts using a web browser on Windows. If I look for a Windows article, I only find guidance for using Outlook - which is not what I'm after.