Here is how to get to the Ikebukuro School from JR Seibu Exit
(Picture 12) The OCE office building has the following signs outside the building. You will see Olive Spa, LIPTY, A Manga Cafe and St. Marc Bakery and Cafe (サンマルクカフェ).
(Picture 12) Enter the building and go to the 6th floor (Picture 13)
(Picture 14) The school entrance is on the right. Congratulations, you made it!