From the shortlist page, simply drag a candidate’s name from the left to the main panel. You will then see their thumbnail, plus some additional data such as when the interview was recorded and their score.
Jump back to their review page during the process to refresh your memory and decide who to take forward to the next stage.
You can contact a candidate directly by clicking on the email link on their tile.
From the review page, you can also click on one of the statuses. This automatically updates the shortlist view.