Q: how can I restore phone from icloud on an earlier IOS (8.2) on my new iphone 6 thats on ios 8.3?

Did you manage to find a way around this as I have the same problem?

You should have no issue restoring a backup made on iOS 8.2 to an iPhone running iOS 8.3

Do you get any error messages whey try to do this?

Hey, this happened to me too. Try this: If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

I have the same issue but I think that my old phone has IOS 8.3 but my new phone is an older version but I can't update it because it is just starting up

Set the new phone up as new, and update to iOS 8.3 when you are done.

After that you can restore the new iPhone, and it will keep the new iOS version, and you should be able to restore from a backup.

Phil has the right idea.
See article here https://support.apple.com/en-us/HT203434

I got it thanks, set up replaced phone as new phone then I updated the software,  then I erased phone and restarted . It works!