How do I start a Family group on a non apple device like an android or windows device?

You can't sign in with Apple ID and password on an android device , it's impossible to create family sharing on it .

Android device is not compatible with setting up iCloud account .

Your question is not for Apple Music .

See the article Set up Family Sharing on iPhone - Apple Support

Family Sharing is available on eligible devices. See the Apple Support article System requirements for iCloud.

Apple claims this is possible on Android:

'Use Family Sharing with Apple Music on Android'. Click on this link to learn how -->

https://support.apple.com/HT212154

"How to start and manage your own family group

When you get an Apple Music family subscription, you can start and manage a family group to share your subscription."

As for Windows, you cannot set up FS on Windowss but you can participate if invited.

Use Family Sharing to share iTunes Store purchases on PC

https://support.apple.com/guide/itunes/family-sharing-itns42f7b0d0/windows

"To use Family Sharing, you need an Apple ID, and you must be invited to join a family group."

Hi,

Sorry to hear you are having issues with setting up Family Sharing.

If you are creating a Family Sharing group, this must be done via device Settings on an iOS, iPadOS, or macOS device.

You only have to be signed into one of the above devices for the purpose of creating the family. After created, you may sign into your preferred device as normal.

https://support.apple.com/en-us/HT201088

I don’t think you can set up family members to be part of your Family Sharing without an Apple device. I looked at iCloud.com, but it says you can do it from Settings on iOS or System Preferences on Mac. It sounds like you’ll need some type of Apple device to do this.

The Apple Recommended post is in direct contradiction to what Apple's own documentation says. You did not say in what context you wished to do this so even if it is only possible in one way then the answer I provided you was correct. You can do it, but only with Apple Music.

"You can't sign in with Apple ID and password on an android device," is also not strictly correct. No, you can't the way you can with an iPhone to use a bunch of Apple features using dedicated apps (apart from Apple Music), but you can sign in through a browser on anything that can run a web browser.

By the way, you can also set up iCloud mail using an Android based mail client. This is going beyond the Family Sharing context but it shows that some of the statements made are not strictly accurate and you should hesitate about taking them as such even though recommended.

And you can sign into iCloud email using a third party email client. So, as you can see, there are indeed multiple ways you can sign in/use iCloud on an Android. There are just a bunch of features an Apple products user can do that you cannot do with an Android device, particularly when it comes to Family Sharing. I was focussing on the positive aspects for you. Others, including the reviewer, were concentrating on the negative and even then not being strictly accurate in doing so.