Network service checks allow you to monitor external access to your servers and webpages. To add a network service check to an existing server you will first need to select a server from the Instances drawer on the left.
Then select the server you would like to add the check to from the tree to the left and click on it. On this new page, scroll down until you the monitoring section. Click +Add Monitoring to access the monitoring catalog.
This new page will show you the checks you already have configured, the services detected on the server that are available to be monitored, and then the rest of the catalog of available checks and plugins below that.
Select the check type you'd like to add by clicking the orange Add button on the card. In this case, we'll choose HTTP. Clicking +Add will open a drawer of available check types from the right, in this case we see: HTTP, HTTP Multistep, and HTTP Port. Select your check type and click +Add.
Once configuration is complete, click Add Check in the bottom right, and your new check has been configured!