By default, Surfer shows you 47 search results on the graph. You may want to analyze just a few of them on the graph or in the Audit.
By clicking "Exclude all pages" with the eye icon under a graph, you can start choosing your pages from scratch and choose the ones that have similar user intent or you simply want to compete against.
To include a page in the analysis, click the eye icon next to the page title in SERP.
All in all, if you want to:
prepare audit based on picked URL's
challenge your page against a few competitors
make sure that you are looking at eg. TOP3 performances only...
Then "exclude all pages" is for you. :)
After you excluded all pages, you can pick any of them by clicking an "eye" icon which is next to every URL from the search results below.