Looks like desktop wasn't enabled for your Org. We have enabled it now - please let me know if the issue persists.
Right now Desktop only supports Chalk calls using Connect Codes. Within the mobile Chalk app you can select 'Start a Session'. This will open up a new session screen with a Connect Code displayed. The lab engineer can then use the 'Share' feature below the Connect Code to send the office engineer the Connect Code via whatever method they like (email, text, etc). Once the office engineer has the connect code they can enter it into the Desktop app using the 'Join Session' option to connect to the remote user's session.
Thank you @tmccombie , that worked ok.
We tried a session today but unfortunately got the message below. Is it not possible to use sketches on the screen with Chalk Desktop? Both users are hosts.
Annotations are possible on Chalk for Desktop. Did the 'local user' (the one who was sharing their screen) follow the initial instructions displayed that allows Chalk to map the environment? It looks like this:
Once the local user successfully does that, you should be able to add Chalk marks. I just tested locally and was able to add Chalk marks using Desktop.
Thanks again @tmccombie I'm sure that's what happened. I will tell him to follow the on screen instructions when he starts the session.