From Etchujima (越中島) to Komaba Todai mae (駒場東大前)

Keiyo line (京葉線): Etchujima (越中島) → Tokyo (東京) 

Yamanote line (山の手線): Tokyo (東京) → 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 Tokyo (東京).

See this video for changing trains at Shibuya (渋谷).

Google 「 渋谷駅 構内図 JR 」or 「Shibuya Station Guide map JR」 for  Shibuya station if you think you are trapped.