Zojo-ji Temple is a 5 minute walk from Hamamatsucho Station. Take the North Exit from Hamamatsucho Station, and as soon as you exit, you will see Tokyo Tower in front of you. Walk straight toward the tower for about five minutes, and you will see the gate marking the entance to Zojo-ji Temple.
From Tokyo Station to Hamamatsucho Station:
Take the Yamanote Line direct to Hamamatsucho Station (6 minutes, ¥160)
From Shinjuku Station to Hamamatsucho Station:
Take the Yamanote Line direct to Hamamatsucho Station (27 minutes, ¥200)