You can create an Uptime Monitoring check by clicking on the "CREATE NEW MONITOR" button in the Dashboard or at the left-hand-side menu in the Monitoring section.
You can choose between 3 sub-options: Web, Network and Email.
The next step is to enter the website or service name and URL (alternatively, an IP address).
It is also possible to check if specific content exists or does not exist on your website. Sending custom headers is possible as well.
The last step is to choose who will be alerted once your website or service goes down.