Cohen Lounge is located on the first floor of Dickson Hall.
To reach Dickson Hall from the Red Hawk Deck, exit the parking structure on the first floor and walk up the hill with the Kasser Theater behind you and College Hall (the white building with the bell on top) to your right. Dickson Hall is the first brick building that will be on your left. Enter Dickson Hall, go past the first hallway, and Cohen Lounge is the second room on your right (it is clearly labeled).
You may view an interactive map of this route here.