The four things you'll do most often are create (for making tasks), todo and search (for finding tasks), and done (for finishing tasks).
To get a full list of Hiveminder IM commands, have a look at help commands. For more information about a command, just ask for help commandname.
To work with a specific task (or set of tasks) you can use task ID. For more on this, check out help context.
You can tell us what you think with the feedback command. Enjoy!