After Creating a new host, you should define checks for it:
On the left, choose Hosts.
Locate the host to which you need to add checks, and choose the Edit button in the Actions coulmn.
Use the buttons in the Add check screen area to add checks as needed.
Review the checks defined for the host in the Selected checks screen area.
After defined the checks for your host, it is time for the third and final step. Make sure you would be notified when some check fails as described in Setting a notification.
For more information about how to configure direct checks for the system you want to monitor, see Managing checks.