Well unlike others here sync is working fine for me … well … not really.
I followed the instructions, put a couple of test documents into the “Sync” group in DT. Then “followed the instructions on the screen” as the DTTG phone app tells me to.
Trouble is, the options I get are to sync the global inbox or one of my open databases. No mention of the “Sync” group in DT … in fact I can sync anything BUT the Sync group!!!
What gives? This seems the inverse of what should be happening
When you choose a database, DTTG will sync everything in the Sync group in that database. You can also sync your Global Inbox.
It seems strange to me that one can turn off global inbox syncing. Wouldn’t it be rare someone would want to do that? I’m all for simplfying the UI and removing functions if they overly complicate; desktop DT sure needs some of that. 
ok i get it now … the Sync folder is per database not global, so I have to select the database and then do the sync … that wasnt clear from the instructions.