I think he’s trying to say he wants to play PUBG on both devices but make his primary device the new one
PUBGm does not work like a browser where you can select a default primary device and secondary device
Like how you can do with google chrome or Firefox
Simply log into your PUBGm account with your new phone
And if you have double authentication enabled then your new phone will log in once you enter the code from the text message or email
That’s it.