Original: When Åkerfeldt showed up to practice the day after Isberg invited him, it became clear that Isberg had not told the band members, including the band's current bassist, that Åkerfeldt would be joining.
Simplified: When Åkerfeldt showed up to practice the next day, it became clear that Isberg had not told the band members, including the band's current bassist, that Åkerfeldt would be joining.