There is no clear "How to" link identities without creating a new one. So I improvised after skimming some articles about linking devices.
My main issue with the docs stems from the fact that I don't want to create a duplicate identity and the the first step whenever I launch a fresh install of bittorrent sync is It asks me to create a duplicate identity. I don't see the docs even mentioning how to handle that step.
So on my new desktop I reluctantly created this duplicate identity *sigh* and then I went to Manual Connection and pasted a long code I got from my existing working laptop in the Link Device screen.
But it just hangs on the screen forever. It may be because I'm booting Windows 10 from Grub with a UTC time set from the linux bootmanager. I say it's UTC time because if I choose to sync with the internet time servers, it says it's 1am when it's like, actually still daylight hours here.
It's been hung on this screen for.... over 10 minutes. And I have extremely fast network speed (300mbs WAN internet) and SSDs all optimized for gigabit LAN, ALL on wired connections, no Wi-Fi.