how do i search icloud calendar on windows computer

The biggest reason I still use a google calendar for most of my work is the ability to search events on their web portal; especially for those that are in some way linked by theme or activity (e.g. a medical appointment with preceding laboratory tests; project plan with multiple steps or deliveries, vacation planning, etc.

There is no search function on the web portal, use a client.

Well are you syncing your iCloud calendar to your computer?

What program are you using on your PC to access the iCloud calendar, the default is Outlook, is that what you are using?