First create a file with the right shebang so it can be executed on remote systems. You also need to add the '#fname' header which will determine the filename the script will have on the remote system.
#!/bin/bash
#fname:check-something.sh
if [ 1 -eq 0 ]; then
echo "1 is not equal to 0. Something must be up"
exit 1
fi
Then, you need to add it to monit-script-registry.txt so its part of the scripts that are pulled down on the remote systems.
The rest is magic