From a very high level, the integration works as follows:
Login to Statuspage and find your Page ID and API Key within Manage Account -> API
In a new tab, login to Pingometer and navigate to Account > Extras > Manage (Statuspage.io). Enter the Page ID and API Key into the fields and turn on the integration.
Find the Component ID by navigating to the Components section of your account, clicking Edit by the component in question, and look at the URL after the "/components/" portion.
Go to Monitors > (sub-menu for specific monitor) > Edit > Advanced and enter your Statuspage Component ID. Then, click "Submit".
Test the integration by setting a value of '504' for "Expect Data" (Monitors > Edit > Advanced > Expect Data). This will cause checks to fail which, in turn, will degraded the appropriate component status within Statuspage.