If You want to transfer/copy/migrate GPOs from Domain A to Domain B, You need to:

On Domain A:

  1. Select GPO you want to transfer
  2. Right click ->Backup
  3. Select location where you want to save backup
  4. Backup->Ok.

Copy entire saved folder (name of folder is GUID, something like {6E6C373B-1………………) to Domain B.

On Domain B:

  1. For example: copy backup folder “named by GUID” from Domain A on desktop server Domain B
  2. From that folder copy(not cut) all content out to desktop
  3. Make new GPO
  4. Right click->Import
  5. For “Backup folder” chose Desktop
  6. Next->Next->Finish->OK

Now, You can link Your GPO to OU.

You can delete all files and folders from desktop….