Hotjar generates Heatmaps by taking a screenshot of a page on your site and storing a copy of the HTML elements present on it. The usage data is then transposed on top of the screenshot according to which elements your visitors interact with.
When targeting multiple pages by using Starts with, Ends with, Contains, or Regular Expression as match operators, Hotjar does not have a proper full URL, but a pattern to match URLs with. This means that the first matching page which a visitor reaches will be the page used to generate the screenshot for the heatmap of all of the matching pages.
In some cases, it's preferable to decide which page to use for the screenshot. In such cases, the Custom Screenshot Page URL field is used. This simply tells Hotjar from where it should take the screenshot.
When you use the Custom Screenshot Page URL data from other pages matching the target set will be collected straight away, but no screenshot will be generated until the specified page has been visited and past data collected will then be transposed onto that screenshot.
To specify a URL click the Advanced link and the field will be visible.
If you set the Page URL so that it generates a heatmap for all your article pages on your site/blog as:
Your Custom Screenshot Page URL should be a URL of one of those articles:
The Screenshot Page URL must match the HTML layout of the Page URLs you are targeting.