Multiquery syntax is quite simple, just issuing
multiquery 'command1; command2; command3 &'
will execute command1, command2 and, in the background, command3 (thanks to the '&' parameter).
Another example, if you want to create a directory called "test" on the remote nodes, issue
multiquery 'mkdir test'
Or, if you need to kill a process that you started remotely on all the nodes, you can try
multiquery 'pkill processName'
work in progress