That's kind of the gist of it, yeah! [Aside from the poster machine thing, but he's slowly getting there, so she'll take one little victory at a time.]

It's easier to show you than to just explain. Let me contact a friend...

[She switches on her communicator, and decides to just show him the process rather than bogging him down with more talking. She opens up her (currently very small) contact list and picks someone she knows, typing: Hello! It's Michiru. I'm showing someone how the communicator works, so please can you message me back? Thanks!

Then she hits 'SEND', and then glances at Zuko.]

That message I wrote will reach the other person's communicator. Now we just have to wait for a reply.