At present, Studio can only open a file based or Groupshare based TM. The ability to migrate a TM to the cloud has been added, but there is no way to access an existing cloud based TM directly from Trados Studio.
It would be very helpful either to be able to open a cloud based TM in Trados Studio in the same way as a server based TM - both for TM maintenance, and for small projects that may be translated as single file projects not uploaded to the cloud, and also, when carrying out Alignment, it would be very useful to connect directly to the cloud based TM to add new TUs there, rather than having to work through creating a new file based TM and importing that to the cloud based one.