I’m using a screenshot of a free app called “Kougou KJV” for these lessons. It contains the Japanese Kougouyaku translation and English King James Version, both of which are in the public domain. Checkout and download this great app.
Below is a link to a website with the text as well as the audio of the Gospel of John Chapter 3. Try reading the Japanese and then eventually read while listening to the audio. The plan is to go through all of John Chapter 3 so eventually you should be able to read and listen to the entire Chapter.