How can I install windows 10 on my old 2011 iMac

I'm trying to install Win10_21H1_English_x64 (Windows 10) on my 2011 iMac. Here are the specs:

• Model Identifier: iMac12,1
• Processor Name: Intel Core i5
• Memory: 12 GB
• macOS Sierra 10.12.6

I've been trying to do this for probably a month now, and I can't find anything.

I have the windows 10 iso image and I've tried using Boot Camp Assistant, but I don't know really how to use it.

Here is what I've done so far:

• I open boot camp,
• I click next,
• I choose the USB flash drive,
• Click next, it installs the windows support,
• then says "Plugin windows media and wait a few seconds for it to recognize."

I don't know what that means or how to proceed from here.

Can anyone help me??