I’m skipping the materials that have already been adapted into the anime, i.e. all the way till the second half of volume 5. Also, some anonymous group has translated till v3ch42. You can read them on Batoto.
Update: To those curious, the manga has ended at 7 volumes: 106 chapters focusing on the boys, 26 extra chapters on Habara and co., the “High School Girls are Funky” segment.