There are two routes to the cohort browser. The first is from the large Browse Cohort Listings button on the front page and the second is via the Cohort Listings > Browse Cohorts menu item. If you use either route you will see the Browse Study Cohorts page:
This page lists a summary view of the published study cohorts. A summary view of each cohort is presented on the right hand side and filters for reducing the size of the list are available on the left hand side of the page. If a study has participant data uploaded to the hub then it will have a “Searchable” label in the bottom corner and will be considered available in the large pink Search Within These Studies button at the top of the list. If you click the large pink search button you will be taken to the Search Participant Data page, using the set of searchable studies that you currently have in your catalogue list.