From Monzen-Nakacho (門前仲町) to Komaba Todai mae (駒場東大前)

Toei Oedo line (都営大江戸線): Monzen-Nakacho (門前仲町) → Aoyama-Itchome (青山一丁目)

Hanzomon line (半蔵門線):  Aoyama-Itchome (青山一丁目) → Shibuya (渋谷)

Inokashira line (井の頭線): Shibuya (渋谷) → Komaba Todai mae (駒場東大前)

See this video for changing trains at Aoyama-Itchome (青山一丁目).

See this video for changing trains at Shibuya (渋谷). A5b is the best station entrance for changing trains.