I'm an old player returning to the new version. I can't seem to figure how to activate the teleport stone plates for quick traveling. It works for Calterbury, Winston and Aldyn but not other cities. Or is fast travel simply more restricted in the more recent update?

There is an npc in Lalizan in Dorgania who explains the stone plates to you. The dialog is necessary to be able to active the stone plates in the rest of the world, and to use them for fast travel. Other locations are activated through events, so you can get them even without this dialog.